Biomedical subjects

Michael P LaValley

Publications and source records attributed to Michael P LaValley.

14 recordsLinked to original sources

PubMed2006

Increase in bone marrow lesions associated with cartilage loss: a longitudinal magnetic resonance imaging study of knee osteoarthritis.

OBJECTIVE: Although bone marrow lesions (BMLs) are powerful predictors of joint space loss as visualized on radiographs, the natural history of these lesions, their relationship to cartilage loss, and the association between change in these lesions and cartilage loss are unknown. These questions were tested using longitudinal magnetic resonance imaging (MRI) data in a natural history study of symptomatic knee osteoarthritis (OA). METHODS: MRI of the knee was performed at baseline, 15 months, and 30 months in 217 patients with primary knee OA (122 men, 95 women; mean +/- SD age 66.4 +/- 9.4 years). To assess mechanical alignment, long-limb films were obtained at 15 months. Subchondral bone marrow abnormalities, graded in the medial and lateral tibiofemoral joints, were defined as poorly marginated areas of increased signal intensity in the marrow on fat-suppressed, T2-weighted images. Cartilage morphologic features in the medial and lateral tibiofemoral joints were scored at all time points using a semiquantitative scale. For each of the medial and lateral compartments, generalized estimating equations were used to evaluate the longitudinal relationship of tibiofemoral BMLs to the tibiofemoral cartilage score, with adjustment for malalignment. RESULTS: Fifty-seven percent of knees had BMLs at baseline, of which 99% remained the same or increased in size at followup. Knee compartments with a higher baseline BML score had greater cartilage loss. An increase in BMLs was strongly associated with further worsening of the cartilage score. Enlarging or new BMLs occurred mostly in malaligned limbs, on the side of the malalignment (e.g., new medial BMLs in varus-aligned knees). The association of BML change with medial tibiofemoral cartilage loss was not significant after adjusting for alignment. CONCLUSION: Lesions of the bone marrow are unlikely to resolve and often get larger over time. Compared with BMLs that stay the same, enlarging BMLs are strongly associated with more cartilage loss. Furthermore, any change in BML is mediated by limb alignment.

Aged↗

PubMed2005

Prospective studies of dairy product and calcium intakes and prostate cancer risk: a meta-analysis.

BACKGROUND: The Dietary Guidelines for Americans 2005 recommends that Americans increase their intake of dairy products. However, some studies have reported that increasing dairy product intake is associated with an increased risk of prostate cancer. We conducted a meta-analysis to examine associations between intakes of calcium and dairy products and the risk of prostate cancer. METHODS: We searched Medline for prospective studies published in English-language journals from 1966 through May 2005. We identified 12 publications that used total, advanced, or fatal prostate cancer as end points and reported associations as relative risks (RRs) with 95% confidence intervals (CIs) by category of dairy product or calcium intake. Data were extracted using standardized data forms. Random-effects models were used to pool study results and to assess dose-response relationships between dairy product or calcium intakes and the risk of prostate cancer. We conducted sensitivity analyses by changing criteria for inclusion of studies or by using fixed-effects models. All statistical tests were two-sided. RESULTS: Men with the highest intake of dairy products (RR =1.11 [95% CI = 1.00 to 1.22], P = .047) and calcium (RR = 1.39 [95% CI = 1.09 to 1.77], P = .018) were more likely to develop prostate cancer than men with the lowest intake. Dose-response analyses suggested that dairy product and calcium intakes were each positively associated with the risk of prostate cancer (Ptrend = .029 and .014, respectively). Sensitivity analyses generally supported these associations, although the statistical significance was attenuated. The pooled relative risks of advanced prostate cancer were 1.33 (95% CI = 1.00 to 1.78; P = .055) for the highest versus lowest intake categories of dairy products and 1.46 (95% CI = 0.65 to 3.25; P > .2) for the highest versus lowest intake categories of calcium. CONCLUSIONS: High intake of dairy products and calcium may be associated with an increased risk of prostate cancer, although the increase appears to be small.

Calcium, Dietary↗

PubMed2005

The relationship between cartilage loss on magnetic resonance imaging and radiographic progression in men and women with knee osteoarthritis.

OBJECTIVE: To determine the relationship between radiographic progression of joint space narrowing and cartilage loss on magnetic resonance imaging (MRI) in patients with symptomatic knee osteoarthritis (OA), and to investigate the location of MRI-based cartilage loss in the knee and its relation to radiographic progression. METHODS: Two hundred twenty-four men and women (mean age 66 years) were studied. Radiographs and MRI of the more symptomatic knee were obtained at baseline and at 15- and 30-month followup. Radiographs of the knee (with weight-bearing) were read for joint space narrowing (scale 0-3), with progression defined as any worsening in score. We used a semiquantitative method to score cartilage morphology in all 5 regions of the tibiofemoral joint, and defined cartilage loss as an increase in score (scale 0-4) at any region. We examined the relationship between progression of joint space narrowing on radiographic images and cartilage loss on MRI, using a generalized estimating equation proportional odds logistic regression, adjusted for baseline cartilage score, age, body mass index, and sex. The medial and lateral compartments were analyzed separately. RESULTS: In the medial compartment, 104 knees (46%) had cartilage loss detected by MRI. The adjusted odds ratio was 3.7 (95% confidence interval 2.2-6.3) for radiographic progression being predictive of cartilage loss on MRI. However, there was still a substantial proportion of knees (80 of 189 [42%]) with cartilage loss visible on MRI when no radiographic progression was apparent. Cartilage loss occurred frequently in the central regions of the femur and tibia as well as the posterior femur region, but radiographic progression was less likely to be observed when posterior femur regions showed cartilage loss. Radiographic progression appeared specific (91%) but not sensitive (23%) for cartilage loss. Overall findings were similar for the lateral compartment. CONCLUSION: While our results provide longitudinal evidence that radiographic progression of joint space narrowing is predictive of cartilage loss assessed on MRI, radiography is not a sensitive measure, and if used alone, will miss a substantial proportion of knees with cartilage loss.

Aged↗

PubMed2005

The lateral view radiograph for assessment of the tibiofemoral joint space in knee osteoarthritis: its reliability, sensitivity to change, and longitudinal validity.

OBJECTIVE: To evaluate the reliability, validity, and sensitivity to change of tibiofemoral (TF) narrowing on lateral radiographic views. METHODS: In a natural history study of symptomatic knee osteoarthritis (OA), both lateral view and fluoroscopically positioned posteroanterior (PA) semiflexed view radiographs of the knee in 30 degrees of flexion and with weight bearing were obtained at baseline and at 30 months. Test-retest reliability was evaluated using repeat radiographs, with joint space width measured using electronic calipers. All radiographs were scored on a 0-3 scale, and progression of joint space loss was defined as narrowing of the joint space by 1 grade. We evaluated sensitivity to change compared with the PA view. We evaluated validity by examining whether knees with progression showed expected malalignment on full-limb films. RESULTS: Test-retest reliability of the TF joint space using the lateral view had a root mean square error of 0.303 mm, with 92.5% of repeats within 1 mm. More knees showed progression on the lateral view alone (n = 41) than on the PA view alone (n = 27). Compared with knees without joint space loss, knees with medial compartment loss on the lateral view only were more varus malaligned (P < 0.001), while those with lateral compartment loss were more valgus malaligned (P = 0.008). CONCLUSION: In the assessment of TF joint space loss, lateral view radiographs are reliable, valid, and more sensitive to change than fluoroscopically positioned PA radiographs.

Cartilage, Articular↗

PubMed2004

Knee adduction moment and development of chronic knee pain in elders.

OBJECTIVE: To determine whether the adduction moment at the knee during locomotor activity contributes to the development of future chronic knee pain. METHODS: We studied 132 community-dwelling elders who had undergone a full kinetic and kinematic motion analysis while performing 4 different activities: standing, walking, rising from a chair, and descending stairs. We contacted the participants 3-4 years after their baseline locomotion analysis and identified those who reported no knee pain at the time of motion analysis but who subsequently developed new chronic knee pain at followup. We examined whether the development of new chronic knee pain was associated with higher peak adduction moment at the knee during activities, measured at baseline. RESULTS: Of the 132 elders evaluated in 1995-1996, 118 (89%) were contacted in 1999. Of the 118 contacted, 80 (mean age 75 years; 78% women) had no lower extremity prosthetic joints at baseline, no known underlying inflammatory arthritis at baseline nor followup, and no baseline knee pain. At followup, 7 had developed new chronic knee pain defined as pain or stiffness on most days of the month and with walking 2 blocks or using stairs. Compared with those who did not develop knee pain, those who did develop new chronic knee pain had higher baseline adduction moments for all activities (P = 0.01), ranging from 8% higher during chair rise to 39% higher during stair descent. CONCLUSION: We found that greater adduction moment at the knee during activities contributes to the development of future chronic knee pain. Our results suggest that biomechanical factors may play an important role in the pathogenesis of knee pain and should be studied further.

Aged↗

PubMed2003

Bone marrow edema and its relation to progression of knee osteoarthritis.

BACKGROUND: While factors affecting the course of knee osteoarthritis are mostly unknown, lesions on bone scan and mechanical malalignment increase risk for radiographic deterioration. Bone marrow edema lesions on magnetic resonance imaging correspond to bone scan lesions. OBJECTIVE: To determine whether edema lesions in the subarticular bone in patients with knee osteoarthritis identify knees at high risk for radiographic progression and whether these lesions are associated with limb malalignment. DESIGN: Natural history study. SETTING: A Veterans Administration hospital in Boston, Massachusetts. PATIENTS: Persons 45 years of age and older with symptomatic knee osteoarthritis. MEASUREMENTS: Baseline assessments included magnetic resonance imaging of the knee and fluoroscopically positioned radiography. During follow-up at 15 and 30 months, patients underwent repeated radiography; at 15 months, long-limb films were obtained to assess mechanical alignment. Progression was defined as an increase over follow-up in medial or lateral joint space narrowing, based on a semi-quantitative grading. Generalized estimating equations were used to evaluate the relation of medial bone marrow edema lesions to medial progression and lateral lesions to lateral progression, before and after adjustment for limb alignment. RESULTS: Of 256 patients, 223 (87.1%) participated in at least one follow-up examination. Medial bone marrow lesions were seen mostly in patients with varus limbs, and lateral lesions were seen mostly in those with valgus limbs. Twenty-seven of 75 knees with medial lesions (36.0%) showed medial progression versus 12 of 148 knees without lesions (8.1%) (odds ratio for progression, 6.5 [95% CI, 3.0 to 14.0]). Approximately 69% of knees that progressed medially had medial lesions, and lateral lesions conferred a marked risk for lateral progression. These increased risks were attenuated by 37% to 53% after adjustment for limb alignment. CONCLUSION: Bone marrow edema is a potent risk factor for structural deterioration in knee osteoarthritis, and its relation to progression is explained in part by its association with limb alignment.

Aged↗

PubMed2003

Bias due to missing exposure data using complete-case analysis in the proportional hazards regression model.

We studied bias due to missing exposure data in the proportional hazards regression model when using complete-case analysis (CCA). Eleven missing data scenarios were considered: one with missing completely at random (MCAR), four missing at random (MAR), and six non-ignorable missingness scenarios, with a variety of hazard ratios, censoring fractions, missingness fractions and sample sizes. When missingness was MCAR or dependent only on the exposure, there was negligible bias (2-3 per cent) that was similar to the difference between the estimate in the full data set with no missing data and the true parameter. In contrast, substantial bias occurred when missingness was dependent on outcome or both outcome and exposure. For models with hazard ratio of 3.5, a sample size of 400, 20 per cent censoring and 40 per cent missing data, the relative bias for the hazard ratio ranged between 7 per cent and 64 per cent. We observed important differences in the direction and magnitude of biases under the various missing data mechanisms. For example, in scenarios where missingness was associated with longer or shorter follow-up, the biases were notably different, although both mechanisms are MAR. The hazard ratio was underestimated (with larger bias) when missingness was associated with longer follow-up and overestimated (with smaller bias) when associated with shorter follow-up. If it is known that missingness is associated with a less frequently observed outcome or with both the outcome and exposure, CCA may result in an invalid inference and other methods for handling missing data should be considered.

Alleles↗

PubMed2003

Arthritis self-management education programs: a meta-analysis of the effect on pain and disability.

OBJECTIVE: Some reports suggest that education programs help arthritis patients better manage their symptoms and improve function. This review of the published literature was undertaken to assess the effect of such programs on pain and disability. METHODS: Medline and HealthSTAR were searched for the period 1964-1998. The references of each article were then hand-searched for further publications. Studies were included in the meta-analysis if the intervention contained a self-management education component, a concurrent control group was included, and pain and/or disability were assessed as end points. Two authors reviewed each study. The methodologic attributes and efficacy of the interventions were assessed using a standardized abstraction tool, and the magnitude of the results was converted to a common measure, the effect size. Summary effect sizes were calculated separately for pain and disability. RESULTS: The search strategy yielded 35 studies, of which 17 met inclusion criteria. The mean age of study participants was 61 years, and 69% were female. On average, 19% of patients did not complete followup (range 0-53%). The summary effect size was 0.12 for pain (95% confidence interval [95% CI] 0.00, 0.24) and 0.07 for disability (95% CI 0.00, 0.15). Funnel plots indicated no significant evidence of bias toward the publication of studies with findings that showed reductions in pain or disability. CONCLUSION: The summary effect sizes suggest that arthritis self-management education programs result in small reductions in pain and disability.

Arthritis↗

PubMed2003

Reduction of job loss in persons with rheumatic diseases receiving vocational rehabilitation: a randomized controlled trial.

OBJECTIVE: Job loss is a major consequence of rheumatic diseases, and clinicians may refer patients to vocational rehabilitation for help. When provided after job loss, the impact of vocational rehabilitation is short term. This randomized controlled trial with 48 months of followup was undertaken to determine the efficacy of vocational rehabilitation provided to persons with rheumatic diseases while they are still employed, but at risk for job loss. METHODS: A total of 242 patients with rheumatic diseases residing in Massachusetts were recruited through their rheumatologists for study. Participants were randomly assigned to the experimental group (n = 122) or the control group (n = 120). Subjects in the experimental group received two 1.5-hour sessions of vocational rehabilitation; those in the control group received print materials about disability employment issues and resources by mail. The main outcome assessed was the time to first job loss. Job losses were defined as permanent disability, premature retirement, or a period of unemployment. All analyses were conducted on an intent-to-treat basis. RESULTS: Job loss was delayed in the experimental group compared with the control group (P = 0.03 by log rank test). After adjustment for confounders, participation in the experimental group was found to be protective against job loss (odds ratio 0.58 [95% confidence interval 0.34-0.99], P = 0.05 by pooled logistic regression). CONCLUSION: Vocational rehabilitation delivered to patients at risk for job loss, but while they were still employed, delayed job loss. Such an intervention has the potential to reduce the high indirect costs, as well as the personal impact, of rheumatic diseases.

Adolescent↗

PubMed2002

Truth survival.

Explore the source record for details and available documents.

Bias↗

PubMed2002

Statistical presentation and analysis of ordered categorical outcome data in rheumatology journals.

OBJECTIVE: To assess the appropriateness of presentation of summary measures and analysis of ordered categorical (ordinal) data in three rheumatology journals in 1999, and to consider differences between basic and clinical science articles. METHODS: Six hundred forty-four full-length articles from the 1999 editions of 3 rheumatology journals were evaluated for inclusion of an ordinal outcome. Articles were classified as basic or clinical science, and the appropriateness of presentation and analysis of the ordinal outcome were assessed. Chi-square tests were used to evaluate difference in percentages. RESULTS: Ordinal outcomes were identified in 175 (27.2%) of 644 articles. Only 69 (39.4%) had appropriate data presentation, and 111 (63.4%) had appropriate data analysis. Appropriate presentation was seen less commonly in the basic science rather than the clinical science articles, but differences in the occurrence of appropriate analysis were not seen. CONCLUSION: Ordinal data are common in rheumatology articles, but presentation usually does not conform to recommended guidelines.

Data Collection↗

PubMed2002

Secular changes in the quality of published randomized clinical trials in rheumatology.

OBJECTIVE: To assess the quality of published randomized clinical trials (RCTs) in rheumatology and to determine whether there has been improvement in quality between 2 time periods, 1987-1988 and 1997-1998. METHODS: Using MEDLINE and a hand search of selected rheumatology journals, we identified RCTs of adult rheumatic diseases published in English in 1987-1988 or 1997-1998. We examined trial quality with an expanded version of the Jadad scale, which assesses the adequacy of reported random sequence generation, allocation concealment, blinding, and analysis. All trials were read by 1 reviewer, with prior standardization using a random sample read by 2 reviewers. We also evaluated "high"- versus "low"-impact journals based on citation index. RESULTS: Two hundred forty RCTs (1987-1988 119 RCTs, 1997-1998 121 RCTs) were assessed. Results showed improvement in the quality of the trials, but the rates of reported random sequence generation, allocation concealment, power, and intent-to-treat analyses were persistently low. Low rates of reports of random sequence generation, allocation concealment, and intent-to-treat analyses were present even in the high-impact journals. CONCLUSION: There has been improvement in the quality of reporting of RCTs in rheumatology between 1987-1988 and 1997-1998. However, methodologic problems such as lack of allocation concealment, inadequate random sequence generation, lack of reporting of power, and lack of intent-to-treat analyses remain common. Many of these problems are established sources of bias in RCTs and are easily rectifiable.

Humans↗

PubMed2002

Discrepancy between published report and actual conduct of randomized clinical trials.

Randomized clinical trial (RCT) publications with inappropriate random-sequence generation, lack of allocation concealment, or imperfect blinding yield inflated estimates of effect compared to those in which adequate methods are described. RCTs that do not state methods used yield similar effect estimates, suggesting that inadequate methods were used. We compared RCT publications with investigator reports of actual practice for 40 rheumatology RCTs published in 1997/1998. In RCTs in which these methods were not described in the trial reports and would thus have been characterized as "inadequate," investigators reported using methods of random-sequence generation and allocation concealment that would be considered adequate in 77.4 and 78.1% of RCTs, respectively. This suggests that, in contrast to previous reports, inadequate random-sequence generation and allocation concealment, per se, may not be a major problem in RCTs. Characterizing RCTs as "good" or "poor" quality based on the published report is likely to be inappropriate.

Bias↗

PubMedDate not supplied

Self-management education programs in chronic disease: a systematic review and methodological critique of the literature.

BACKGROUND: Self-management programs have been widely reported to help patients manage symptoms and contain utilization of health care resources for several chronic conditions, but to date no systematic review across multiple chronic diseases has been reported. We evaluated the efficacy of patient self-management educational programs for chronic diseases and critically reviewed their methodology. METHODS: We searched MEDLINE and HealthSTAR for the period January 1, 1964, through January 31, 1999, then hand searched the reference section of each article for other relevant publications. We included studies if a self-management education intervention for a chronic disease was reported, a concurrent control group was included, and clinical outcomes were evaluated. Two authors reviewed each study and extracted the data on clinical outcomes. RESULTS: We included 71 trials of self-management education. Trial methods varied substantially and were suboptimal. Diabetic patients involved with self-management education programs demonstrated reductions in glycosylated hemoglobin levels (summary effect size, 0.45; 95% confidence interval [CI], 0.17-0.74); diabetic patients had improvement in systolic blood pressure (summary effect size, 0.20; 95% CI, 0.01-0.39); and asthmatic patients experienced fewer attacks (log rate ratio, 0.59; 95% CI, 0.35-0.83). Although we found a trend toward a small benefit, arthritis self-management education programs were not associated with statistically significant effects. Evidence of publication bias existed. CONCLUSIONS: Self-management education programs resulted in small to moderate effects for selected chronic diseases. In light of evidence of publication bias, further trials that adhere to a standard methodology would help clarify whether self-management education is worthwhile.

Arthritis↗