Michael Lavalley
Boston University, Biostatistics, Faculty Member
ObjectiveHip abductors, important for controlling pelvic and femoral orientation during gait, may affect knee pain. Our objective was to evaluate the relation of hip abductor strength to worsened or new‐onset frequent knee pain. Given... more
ObjectiveHip abductors, important for controlling pelvic and femoral orientation during gait, may affect knee pain. Our objective was to evaluate the relation of hip abductor strength to worsened or new‐onset frequent knee pain. Given previously noted associations of knee extensor strength with osteoarthritis in women, we performed sex‐specific analyses.MethodsWe used data from the Multicenter Osteoarthritis study. Hip abductor and knee extensor strength was measured. Knee pain was assessed using the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) questionnaire and a question about frequent knee pain at baseline (144‐month visit), and 8, 16, and 24 months thereafter. Knee pain outcomes were worsened knee pain (2‐point increase in WOMAC pain) and incident frequent knee pain (answering yes to the frequent knee pain question among those without frequent knee pain at baseline). Leg‐specific analyses tested hip abductor strength as a risk factor for worsened and new frequent knee pain, adjusting for potential covariates. Additionally, we stratified by knee extensor strength (high versus low).ResultsAmong women, compared to the highest quartile of hip abductor strength, the lowest quartile had 1.7 (95% confidence interval [95% CI] 1.1–2.6) times the odds of worsened knee pain; significant associations were limited to women with high knee extensor strength (odds ratio 2.0 [95% CI 1.1–3.5]). We found no relation of abductor strength to worsening knee pain in men or with incident frequent knee pain in men or women.ConclusionHip abductor weakness was associated with worsening knee pain in women with strong knee extensors, but not with incident frequent knee pain in men or women. Knee extensor strength may be necessary, but not sufficient, to prevent pain worsening.
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ObjectiveHypomagnesemia increases the risk of chondrocalcinosis and calcium pyrophosphate disease. We examined whether the use of drugs that can cause hypomagnesemia, diuretics and proton pump inhibitors (PPIs), increases the risk of... more
ObjectiveHypomagnesemia increases the risk of chondrocalcinosis and calcium pyrophosphate disease. We examined whether the use of drugs that can cause hypomagnesemia, diuretics and proton pump inhibitors (PPIs), increases the risk of chondrocalcinosis.MethodsParticipants in the Multicenter Osteoarthritis (MOST) Study obtained weight‐bearing knee radiographs, and their medication use was recorded at baseline and 30‐, 60‐, 84‐, and 144‐month examinations. We read radiographs serially for chondrocalcinosis and characterized incident chondrocalcinosis when it first appeared. We classified diuretic use as thiazide, loop, and other. To test drug effects on incident chondrocalcinosis at each interval (eg, 30‐60 months), we excluded persons with chondrocalcinosis at the interval’s beginning. For each drug, we evaluated exposure at the beginning and end of the interval. We conducted knee‐based analyses using Bayesian mixed‐effects discrete time survival models adjusted for age, sex, body mass index, radiographic osteoarthritis, race, and clinic site.ResultsOf 5272 knees, 196 developed chondrocalcinosis. Thiazide use (21.7% of examinations) and PPI use (13.7%) were common. Neither loop nor other diuretic use was associated with incident chondrocalcinosis. Thiazide use at the beginning and end of the interval of incidence conferred a high risk (hazard ratio [HR] = 2.18; 95% confidence interval [CI] 1.23‐3.89), but use at the beginning of the interval was not associated with risk (HR = 1.04). PPI use at the interval’s beginning increased risk of chondrocalcinosis (HR = 2.29; 95% CI 1.37‐3.79).ConclusionThiazide diuretics, but not other diuretics, and PPI use probably increase the risk of chondrocalcinosis. These findings may have important clinical implications.
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Objectives:Osteoarthritis (OA) and pain are both made more severe by low-grade inflammation. We examined whether visceral fat, a major source of inflammatory cytokines and adipokines, was associated with an increased risk of knee OA or of... more
Objectives:Osteoarthritis (OA) and pain are both made more severe by low-grade inflammation. We examined whether visceral fat, a major source of inflammatory cytokines and adipokines, was associated with an increased risk of knee OA or of musculoskeletal pain.Methods:Member of the Multicenter Osteoarthritis Study cohort, age 50–79 with or at high risk of knee osteoarthritis had whole body DEXA scans at baseline. At baseline, 30, and 60 months they obtained knee radiographs and MRIs, were asked to score the severity of their knee pain and using a body homunculus, to identify sites of joint pain. We used DEXA scans to measure total body fat and in the torso, visceral fat and subcutaneous fat. We assessed the association of fat depot size with structural outcomes (incident radiographic OA, MRI cartilage loss and synovitis) and with pain outcomes (worsening knee pain, the number of painful joints and widespread pain). Regression analyses were adjusted for age, sex, race, education, smoking, physical activity, BMI and depressive symptoms.Results:At baseline, of 2,961 participants, 60.7% were women; mean age was 62.5 years and BMI 30.5 kg/m2. After adjustment for covariates, no fat measures were associated with any structural outcomes. However, total and visceral but not subcutaneous fat were positively associated with worsening knee pain and widespread pain and the amount of visceral fat was associated with the number of painful joints.Conclusion:Visceral fat was associated with an increased risk of musculoskeletal and widespread pain.
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Objectives:Determine the relationship of patellofemoral osteoarthritis (OA) to changes in performance-based function over 7 years.Methods:2666 participants (62.2±8.0 years, BMI 30.6±5.9kg/m2; 60% female) from the Multicenter... more
Objectives:Determine the relationship of patellofemoral osteoarthritis (OA) to changes in performance-based function over 7 years.Methods:2666 participants (62.2±8.0 years, BMI 30.6±5.9kg/m2; 60% female) from the Multicenter Osteoarthritis Study with knee radiographs at baseline and who completed repeated chair stands and 20-meter walk test at baseline, 2.5, 5, and 7 years were included. Generalized linear models assessed the relation of radiographic patellofemoral OA and radiographic patellofemoral OA with frequent knee pain to longitudinal changes in performance-based function. Analyses were adjusted for age, sex, BMI, tibiofemoral OA, and injury/surgery.Results:Linear models demonstrated a significant group by time interaction for the repeated chair stands (p=0.04) and the 20-meter walk test (p<0.0001). Those with radiographic patellofemoral OA took 1.01seconds longer on the repeated chair stands (p=0.02) and 1.69seconds longer on the 20-meter walk test (p<0.0001) at 7 years compared with baseline. When examining the relation of radiographic patellofemoral OA with frequent knee pain to performance-based function there was a significant group by time interaction for repeated chair stands (p=0.05) and the 20-meter walk test (p<0.0001). Those with radiographic patellofemoral OA with frequent knee pain increased their time on the repeated chair stands by 1.12seconds (p=0.04) and 1.91seconds (p<0.0001) on the 20-meter walk test over 7 years.Conclusion:Individuals with radiographic patellofemoral OA and those with radiographic patellofemoral OA with frequent knee pain have worsening of performance-based function over time. This knowledge may present opportunities to plan for early treatment strategies for patellofemoral OA to limit functional decline over time.
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ObjectiveWe aimed to explore the cross‐sectional relation of unilateral knee pain severity and temporal asymmetry during walking and to determine relations of temporal asymmetry during walking to 2‐year changes in ipsilateral and... more
ObjectiveWe aimed to explore the cross‐sectional relation of unilateral knee pain severity and temporal asymmetry during walking and to determine relations of temporal asymmetry during walking to 2‐year changes in ipsilateral and contralateral knee pain in those with mild‐to‐moderate unilateral knee pain.MethodsThe Multicenter Osteoarthritis Study is a prospective cohort study of adults with or at risk for knee osteoarthritis. The current study included participants with unilateral knee pain. Gait was assessed during self‐selected and fast walking at baseline. Knee pain was assessed at baseline and 2 years. We calculated limb symmetry indices (LSIs; nonpainful limb/painful limb × 100) for stance, single‐limb support time, and double‐limb support time, then examined their relations to unilateral knee pain severity, incident contralateral knee pain, and persistent ipsilateral knee pain.ResultsUnilateral knee pain severity was not associated with temporal asymmetry during self‐selected or fast walking. At 2 years, 17.1% of participants had incident contralateral knee pain and 51.4% had persistent ipsilateral knee pain. For self‐selected walking, greater LSIs (i.e., longer time on the nonpainful limb) for stance and single‐limb support time were associated with decreased odds of incident contralateral knee pain. Measures of temporal asymmetry were not associated with persistent ipsilateral knee pain, except for single‐limb support time during fast walking.ConclusionFor those with unilateral knee pain, temporal asymmetry during walking is not associated with pain severity. However, select measures of stance and single‐limb support time during self‐selected and fast walking relate to longitudinal knee pain outcomes.
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... Interferon-β1ainduced juvenile chronic arthritis in a genetically predisposed young patient with multiple sclerosis: Comment on the case report by Levesque et al. Ricardo Russo MD 1 ,; Silvia Tenembaum MD 1 ,; María J. Moreno PhD 2... more
... Interferon-β1ainduced juvenile chronic arthritis in a genetically predisposed young patient with multiple sclerosis: Comment on the case report by Levesque et al. Ricardo Russo MD 1 ,; Silvia Tenembaum MD 1 ,; María J. Moreno PhD 2 ,; Cristina Battagliotti MD 3. ...
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We developed and validated a set of composite scores that combine quantitative magnetic resonance imaging (MRI)–based measurements of hyaline cartilage damage, bone marrow lesions (BMLs), and effusion‐synovitis into composite scores.
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© Author(s) (or their employer(s)) 2021. Reuse permitted under CC BYNC. No commercial reuse. See rights and permissions. Published by BMJ. Over the last 30 years, treatment for RA has improved dramatically. By the early 2000s, disease... more
© Author(s) (or their employer(s)) 2021. Reuse permitted under CC BYNC. No commercial reuse. See rights and permissions. Published by BMJ. Over the last 30 years, treatment for RA has improved dramatically. By the early 2000s, disease remission had become a realistic goal, although definitions of remission varied widely, making it difficult to compare treatment strategies and gauge how often remission occurred. In 2009, the ACR and the EULAR created a joint committee whose charge was to recommend a definition of remission. Members of the committee suggested a large number of candidate definitions and using a datadriven consensus process, statisticians and programmers tested these candidates in a bank of RA trial data to see which definitions performed best in predicting longterm good function and lack of radiographic progression. The committee endorsed a stringent definition using measures from the validated core set of outcome measures. After reviewing analysis results, the committee selected two definitions of remission that were approved by the ACR and EULAR. 2 The first was a Boolean version in which, to be classified as having attained remission, a patient had to have tender and swollen joint counts (SJCs) of ≤1, a C reactive protein (CRP) level of ≤1 mg/dL and a patient global assessment of arthritis activity of ≤1 (on a 0–10 scale). The second recommended definition was a score of ≤3 on the Simplified Disease Activity Index (SDAI), a scoring system that is based on the same core set outcome measures. While designed and validated in trials, these definitions could help assess treatment ‘success’ in clinical practice as well as in trials and, in practice, could serve as a ‘treattotarget’ goal for some patients. Like all developed criteria, the ACR/ EULAR 2011 RA remission criteria were labelled as provisionally approved and awaited validation in an independent sample for final approval. A revised validated version of the remission criteria is pending for full approval by ACR/EULAR. Many concerns have arisen since the publication of the provisional remission criteria. Among them is the continuing Editor's note
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Background Parkinson disease (PD) is a debilitating and chronic neurodegenerative disease resulting in ambulation difficulties. Natural walking activity often declines early in disease progression despite the relative stability of motor... more
Background Parkinson disease (PD) is a debilitating and chronic neurodegenerative disease resulting in ambulation difficulties. Natural walking activity often declines early in disease progression despite the relative stability of motor impairments. In this study, we propose a paradigm shift with a “connected behavioral approach” that targets real-world walking using cognitive-behavioral training and mobile health (mHealth) technology. Methods/design The Walking and mHealth to Increase Participation in Parkinson Disease (WHIP-PD) study is a twelve-month, dual site, two-arm, randomized controlled trial recruiting 148 participants with early to mid-stage PD. Participants will be randomly assigned to connected behavioral or active control conditions. Both conditions will include a customized program of goal-oriented walking, walking-enhancing strengthening exercises, and eight in-person visits with a physical therapist. Participants in the connected behavioral condition also will (1) r...
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ObjectiveTo investigate thresholds of strength below which individuals with knee osteoarthritis (OA) may have more difficulty carrying out physical functions of daily life. Individuals below such thresholds might benefit more from... more
ObjectiveTo investigate thresholds of strength below which individuals with knee osteoarthritis (OA) may have more difficulty carrying out physical functions of daily life. Individuals below such thresholds might benefit more from strengthening interventions than those with greater strength.MethodsWe studied individuals with symptomatic OA at baseline in the Multicenter Osteoarthritis Study who had knee extensor strength measured isokinetically at 60º/second. Participants underwent a 20‐meter walk test and a sit‐to‐stand test and answered questions from the Western Ontario and McMaster Universities Osteoarthritis Index. Physical function results were plotted against measures of quadriceps strength (Nm) (and as strength:body weight) for the worst knee. Loess technique was used to examine inflection points. Nonlinear relationships were examined in piecewise linear regression models. Differences were tested using linear and logistic regression models.ResultsThe study had 834 participan...
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ObjectiveWork disability rates are high among people with rheumatic and musculoskeletal conditions. Effective disability preventive programs are needed. We examined the efficacy of a modified vocational rehabilitation approach delivered... more
ObjectiveWork disability rates are high among people with rheumatic and musculoskeletal conditions. Effective disability preventive programs are needed. We examined the efficacy of a modified vocational rehabilitation approach delivered by trained occupational therapists and physical therapists on work limitation and work loss over 2 years among people with rheumatic and musculoskeletal conditions.MethodsEligibility criteria for this single‐blind, parallel‐arm randomized trial included ages 21–65 years, 15 or more hours/week employment, a self‐reported doctor‐diagnosed rheumatic or musculoskeletal condition, and concern about staying employed. The intervention consisted of a 1.5‐hour meeting, an action plan, written materials on employment supports, and telephone calls at 3 weeks and 3 months. Control group participants received the written materials. The primary outcome was the Work Limitations Questionnaire (WLQ) output job demand subscale. The secondary outcome was work loss. Int...
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Objective Older adults with knee osteoarthritis (OA) who live in environments with mobility barriers may be at greater risk of developing participation restrictions, defined as difficulties in engagement in life situations. We... more
Objective Older adults with knee osteoarthritis (OA) who live in environments with mobility barriers may be at greater risk of developing participation restrictions, defined as difficulties in engagement in life situations. We investigated the risk of participation restriction over 5 years due to self-reported environmental features among older adults with knee OA. Methods Participants from the Multicenter Osteoarthritis Study (MOST) self-reported participation at baseline, 30 months, and 60 months using the Instrumental Role subscale of the Late Life Disability Index (LLDI). Data on self-reported environmental features were from the Home and Community Environment questionnaire administered in the MOST-Knee Pain & Disability study, an ancillary study of MOST. The relative risks of developing participation restriction at 60 months, indicated by an LLDI score <67.6/100, due to reported high community mobility barriers and high transportation facilitators were calculated using robus...
Research Interests: Psychology, Perception, Medicine, Osteoarthritis, Prospective studies, and 15 moreHumans, Female, Male, Poisson regression, Risk factors, Clinical Sciences, Aged, Middle Aged, Longitudinal Studies, Environment Design, Risk Factors, Confidence Interval, Relative Risk, Mobility limitation, and Residence Characteristics
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Research Interests: Psychology, Rheumatology, Immunology, Clinical Trial, Treatment Outcome, and 15 moreRheumatoid Arthritis, Medicine, Physical Therapy, Humans, Internal Medicine, Placebo, Data Collection, Clinical Sciences, Public health systems and services research, Reproducibility of Results, Rheumatism, Disease Activity, Clinical Trials as Topic, Multicenter Studies as Topic, and Combination Therapy
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Objective. To evaluate the prognosis of tall cell variant (TCV) compared to usual variant (UV) papillary thyroid cancer by comparing disease-related mortality and recurrence data from published studies.Methods. Ovid MEDLINE keyword search... more
Objective. To evaluate the prognosis of tall cell variant (TCV) compared to usual variant (UV) papillary thyroid cancer by comparing disease-related mortality and recurrence data from published studies.Methods. Ovid MEDLINE keyword search using “tall cell variant papillary thyroid cancer” was used to identify studies published in English that calculated disease-related mortality and recurrence rates for both TCV and UV.Results. A total of 131 cases of tall cell variant papillary thyroid cancer were reviewed. The combined odds ratio of recurrence for TCV compared to UV is 4.50 with a 95% confidence interval from 2.90 to 6.99. For disease-related mortality, the combined odds ratio for TCV was compared to UV of 14.28 with a 95% confidence interval from 8.01 to 25.46.Conclusion. Currently published data suggests that TCV is a negative prognostic indicator in papillary thyroid cancer and requires aggressive therapy. This meta-analysis provides the largest prognostic data series on TCV in...
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OBJECTIVE Inflammation worsens joint destruction in osteoarthritis (OA) and aggravates pain. Saturated and n-6 fatty acids (FAs) increase, whereas n-3 FAs reduce inflammation. We examined whether FA levels affected the development of OA.... more
OBJECTIVE Inflammation worsens joint destruction in osteoarthritis (OA) and aggravates pain. Saturated and n-6 fatty acids (FAs) increase, whereas n-3 FAs reduce inflammation. We examined whether FA levels affected the development of OA. DESIGN We studied participants from the Multicenter Osteoarthritis study (MOST) at risk of developing knee OA. After baseline, repeated knee x-rays and MRIs were obtained and knee symptoms queried through 60 month follow-up. Using baseline fasting samples, serum FAs were analyzed with standard assays. After excluding participants with baseline OA, we defined two sets of cases: those developing radiographic OA and those developing symptomatic OA (knee pain and radiographic OA). Controls did not develop these outcomes. Additionally, we examined worsening of MRI cartilage loss and synovitis and of knee pain using WOMAC and evaluated the number of hand joints affected by nodules. In regression models, we tested the association of each OA outcome with levels of saturated, n-3 and n-6 FAs adjusting for age, sex, BMI, education, race, baseline pain and depressive symptoms. RESULTS We studied 260 cases with incident symptomatic and 259 with incident radiographic OA. Mean age was 61 years (61% women). We found no signficant nor suggestive associations of FA levels with incident OA (e.g. for incident symptomatic OA, OR per s.d. increase in n-3 FA 1.00 (0.85, 1.18) nor with any OA outcome in knee or hand. CONCLUSION Despite previously described effects on systemic inflammation, blood levels of FAs were not associated with risk of later knee OA or other OA outcomes.
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The morbidity and lethality of AL amyloidosis is caused by the deposition of lg light chains as fibrillar amyloid protein in vital organs, disrupting their function, and not by the generally low burden of clonal plasma cells that produce... more
The morbidity and lethality of AL amyloidosis is caused by the deposition of lg light chains as fibrillar amyloid protein in vital organs, disrupting their function, and not by the generally low burden of clonal plasma cells that produce the paraproteins. Survival of patients with AL amyloidosis is no more than 1 to 2 years from the time of diagnosis with current management approaches. Clearly, more effective therapies are needed for this rapidly lethal disease. Five patients were treated with dose-intensive melphalan and blood stem cell support and followed for a period of 1 year. Patients were diagnosed with AL amyloidosis by tissue biopsy and categorized by performance status and organ involvement. Their plasma cell dyscrasias were evaluated with immunofixation electrophoresis of serum and urine specimens, quantitative serum lgs, and immunohistochemical staining of bone marrow biopsy specimens. After treatment with dose-intensive intravenous melphalan followed by infusion of auto...
Research Interests: Medicine, Humans, Female, Feasibility Studies, Blood, and 15 moreMultiple Myeloma, Male, Clinical Sciences, Middle Aged, Adult, Hepatomegaly, Cardiomyopathies, AL amyloidosis, Amyloidosis, Nephrotic syndrome, Hematopoietic Stem Cell Transplantation, Gastrointestinal Diseases, neutropenia, Cardiovascular medicine and haematology, and Paediatrics and reproductive medicine
Many persons with knee pain have joint pain outside the knee but despite the impact and high frequency of this pain, its distribution and causes have not been studied. Those studying gait abnormalities have suggested that knee pain causes... more
Many persons with knee pain have joint pain outside the knee but despite the impact and high frequency of this pain, its distribution and causes have not been studied. Those studying gait abnormalities have suggested that knee pain causes pain in adjacent joints but pain adaptation strategies are highly individualized. We studied persons age 50-79 years with or at high risk of knee osteoarthritis drawn from two community-based cohorts, the Multicenter Osteoarthritis Study and the Osteoarthritis Initiative and followed for 5-7 years. We excluded those with knee pain at baseline and compared those who developed and did not develop knee pain at the first follow-up examination (the index visit). We examined pain on most days at joint regions outside the knee in examinations after the index visit. Logistic regression analyses examined the risk of joint specific pain adjusted for age, sex, BMI, depression with sensitivity analyses excluding those with widespread pain. In the combined coho...
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Research Interests: Stem Cell and Light chain
Research Interests: Immunology, Magnetic Resonance Imaging, Natural History, Medicine, Logistic Regression, and 15 moreOsteoarthritis, Humans, Cartilage, Female, Male, Boston, Clinical Sciences, Aged, Middle Aged, Knee Osteoarthritis, Biological markers, Observational Study, Case Control Study, Confidence Interval, and Magnetic resonance image
To evaluate if optimal dose of either oral or injectable regimens of methotrexate (MTX) of 25 mg/week was used in the comparator arms of studies comparing biologic drugs with MTX in rheumatoid arthritis (RA). A systematic literature... more
To evaluate if optimal dose of either oral or injectable regimens of methotrexate (MTX) of 25 mg/week was used in the comparator arms of studies comparing biologic drugs with MTX in rheumatoid arthritis (RA). A systematic literature search was carried out in MEDLINE, EMBASE and the Cochrane Library databases for randomised controlled trials comparing biologics with MTX in RA. A systematic review was performed among studies that met predefined criteria focusing on assessment of dose of MTX used in the comparator arm. Study authors were contacted when necessary. Study quality was assessed. A total of 3276 references were identified and 13 trials were included. We obtained maximal dose and regimen for all. The maximal dose of MTX used in the comparator arm of the trials was no more than 20 mg/week in any trial and for all but one trial, MTX was given orally and not by injection. The trial that used an injectable form reached a maximum of 15 mg/week. A suboptimal dose of MTX was used in...
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In trials of novel immuno-oncology drugs, the proportional hazards (PH) assumption often does not hold for the primary time-to-event (TTE) efficacy endpoint, likely due to the unique mechanism of action of these drugs. In practice, when... more
In trials of novel immuno-oncology drugs, the proportional hazards (PH) assumption often does not hold for the primary time-to-event (TTE) efficacy endpoint, likely due to the unique mechanism of action of these drugs. In practice, when it is anticipated that PH may not hold for the TTE endpoint with respect to treatment, the sample size is often still calculated under the PH assumption, and the hazard ratio (HR) from the Cox model is still reported as the primary measure of the treatment effect. Sensitivity analyses of the TTE data using methods that are suitable under non-proportional hazards (non-PH) are commonly pre-planned. In cases where a substantial deviation from the PH assumption is likely, we suggest designing the trial, calculating the sample size and analyzing the data, using a suitable method that accounts for non-PH, after gaining alignment with regulatory authorities. In this comprehensive review article, we describe methods to design a randomized oncology trial, cal...
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Key Points Question Is bariatric surgical weight loss intervention for obesity associated with microvascular and macrovascular outcomes, and are they differentially associated with sex, race, and metabolic status? Findings In 307... more
Key Points Question Is bariatric surgical weight loss intervention for obesity associated with microvascular and macrovascular outcomes, and are they differentially associated with sex, race, and metabolic status? Findings In 307 individuals with obesity who were followed up after bariatric surgery, the procedure was associated with significant weight loss and improvement in both macrovascular and microvascular function across subgroups of sex, race, and traditional metabolic syndrome. Biomarker assessment using high-sensitivity C-reactive protein plasma levels of greater than 2 mg/dL identified individuals with seemingly metabolically healthy obesity and low-grade inflammation who also derived microvascular benefit from weight loss surgery. Meaning These findings suggest that the beneficial effects of weight loss surgery extend broadly across sex, race, and certain metabolically healthy subgroups.
The 2015 WHO recommendation to initiate all HIV patients on antiretroviral therapy (ART) at diagnosis could potentially overextend health systems and crowd out sicker patients, mitigating the policy's impact. We evaluate whether South... more
The 2015 WHO recommendation to initiate all HIV patients on antiretroviral therapy (ART) at diagnosis could potentially overextend health systems and crowd out sicker patients, mitigating the policy's impact. We evaluate whether South Africa's prior eligibility expansion from CD4 ≤200 to CD4 ≤350 cells/μL reduced ART uptake in the sickest patients. Using data on all patients presenting to the Hlabisa HIV Treatment and Care Program in KwaZulu-Natal from April 2010 - June 2012 (n=13,809), we assessed the impact of the August 2011 eligibility expansion on the number of patients seeking care, number initiating ART, and time from HIV diagnosis to ART initiation among patients always eligible (CD4 0-200), newly eligible (CD4 201-350), and not yet eligible by CD4 count (>350). We used interrupted time series methods to control for long-run trends and isolate the effect of the policy. Expanding ART eligibility led to an increased number of patients initiating ART per month [+95.5...
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To evaluate changes in pain (at the knee and elsewhere) and pain sensitization in obese persons with knee pain undergoing bariatric surgery compared with similarly obese persons undergoing medical management. Individuals undergoing... more
To evaluate changes in pain (at the knee and elsewhere) and pain sensitization in obese persons with knee pain undergoing bariatric surgery compared with similarly obese persons undergoing medical management. Individuals undergoing bariatric surgery and medical management were recruited. Knee pain severity of the more painful knee (index knee) was assessed at baseline and 12 months using the WOMAC. Pressure pain threshold (PPT) was assessed at the index patella and the right wrist. Low patella PPT may reflect peripheral and/or central sensitization and low wrist PPT may reflect central sensitization Mean change in measures of pain and pain sensitization was assessed in the surgery and medical management groups separately. 45 individuals in the surgery group and 22 in the medical management group completed baseline and follow-up visits. The mean weight loss was 32.7 kilograms (29.0%) and 4.6 kilograms (4.1%) in the surgery and medical management groups, respectively. Knee pain decrea...
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Smoking is associated with an increased risk of psoriatic arthritis (PsA) in the general population, but not among patients with psoriasis. We sought to clarify the possible methodological mechanisms behind this paradox. Using 1995-2015... more
Smoking is associated with an increased risk of psoriatic arthritis (PsA) in the general population, but not among patients with psoriasis. We sought to clarify the possible methodological mechanisms behind this paradox. Using 1995-2015 data from The Health Improvement Network, we performed survival analysis to examine the association between smoking and incident PsA in the general population and among patients with psoriasis. We clarified the paradox using mediation analysis and conducted bias sensitivity analyses to evaluate the potential impact of index event bias and quantify its magnitude from uncontrolled/unmeasured confounders. Of 6.65 million subjects without PsA at baseline, 225 213 participants had psoriasis and 7057 developed incident PsA. Smoking was associated with an increased risk of PsA in the general population (HR 1.27; 95% CI 1.19 to 1.36), but with a decreased risk among patients with psoriasis (HR 0.91; 95% CI 0.84 to 0.99). Mediation analysis showed that the ef...
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Objective Participation restriction, common among people with knee osteoarthritis (OA), may be influenced by positive and negative affect. We examined the risk of incident participation restriction over 84 months conferred by positive and... more
Objective Participation restriction, common among people with knee osteoarthritis (OA), may be influenced by positive and negative affect. We examined the risk of incident participation restriction over 84 months conferred by positive and negative affect among people with knee OA. Methods Participants are from the Multicenter Osteoarthritis Study and had or were at high risk of knee OA. Participation restriction and positive and negative affect were measured with the Late Life Disability Index, Instrumental Role Limitation subscale and the positive affect and depressed mood subscales of the Center for Epidemiological Studies Depression Scale, respectively. Robust Poisson regression was used to calculate risk of incident participation restriction over 84 months conferred by combinations of low and high positive and negative affect, adjusting for covariates. Results Of 1810 baseline participants (mean: 62.1 years, 56% female), 470 (26%) had incident participation restriction over 84 months. Participants with low positive affect had 20% greater risk of incident participation restriction than those with high positive affect; participants with high negative affect had 50% greater risk of incident participation compared to those with low negative affect. Participants with both low positive and high negative affect had 80% greater risk of incident participation restriction compared to other combinations of positive and negative affect. Conclusion Low positive and high negative affect, both alone and in combination, increase risk of participation restriction among adults with knee OA. Efforts aimed at preventing participation restriction in this population should consider these mood states. This article is protected by copyright. All rights reserved.
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Purpose Clinicians often test laryngeal sensation by touching the laryngeal mucosa with the tip of a flexible laryngoscope. However, the pressure applied to the larynx by using this touch method is unknown, and the expected responses... more
Purpose Clinicians often test laryngeal sensation by touching the laryngeal mucosa with the tip of a flexible laryngoscope. However, the pressure applied to the larynx by using this touch method is unknown, and the expected responses elicited by this method are uncertain. The variability in pressure delivered by clinicians using the touch method was investigated, and the subject responses to the touches were also reported. Methods A fiberoptic pressure sensor passed through the working channel of a laryngoscope, with its tip positioned at the distal port of the channel. Two examiners each tested 8 healthy adults. Each examiner touched the mucosa covering the left arytenoid 3 times. The sensor recorded the pressure exerted by each touch. An investigator noted subject responses to the touches. From the recorded videos, the absence or presence of the laryngeal adductor reflex in response to touch was judged. Results Pressure values obtained for 46 of the 48 possible samples ranged from...