Gail Tudor

Lifetime risk of symptomatic knee osteoarthritis

OBJECTIVE To estimate the lifetime risk of symptomatic knee osteoarthritis (OA), overall and stratified by sex, race, education, history of knee injury, and body mass index (BMI). METHODS The lifetime risk of symptomatic OA in at least 1 knee was estimated from logistic regression models with generalized estimating equations among 3,068 participants of the Johnston County Osteoarthritis Project, a longitudinal study of black and white women and men age >or=45 years living in rural North Carolina. Radiographic, sociodemographic, and symptomatic knee data measured at baseline (1990-1997) and first followup (1999-2003) were analyzed. RESULTS The lifetime risk of symptomatic knee OA was 44.7% (95% confidence interval [95% CI] 40.0-49.3%). Cohort members with history of a knee injury had a lifetime risk of 56.8% (95% CI 48.4-65.2%). Lifetime risk rose with increasing BMI, with a risk of 2 in 3 among those who were obese. CONCLUSION Nearly half of the adults in Johnston County will develop symptomatic knee OA by age 85 years, with lifetime risk highest among obese persons. These current high risks in Johnston County may suggest similar risks in the general US population, especially given the increase in 2 major risk factors for knee OA, aging, and obesity. This underscores the immediate need for greater use of clinical and public health interventions, especially those that address weight loss and self-management, to reduce the impact of having knee OA.

N-Acetylcysteine for the Prevention of Radiocontrast Induced Nephropathy: A Meta-Analysis of Prospective Controlled Trials

N-acetylcysteine has been recommended for patients with renal insufficiency who are to receive radiocontrast media. However, trials of oral N-acetylcysteine for the prevention of radiocontrast-induced nephropathy have yielded inconsistent results. A systematic review of patient and study characteristics was undertaken to discover possible explanations of the inconsistencies. The databases MEDLINE, EMBASE, and CENTRAL (1966 to March 2003) were searched in all languages, and conference proceedings from several professional societies from the years 1999 to 2003 were also searched. Only prospective controlled trials of oral N-acetylcysteine were included. Risk difference estimates and 95% confidence intervals were calculated. The estimates were examined for evidence of publication bias and heterogeneity. Stratified and meta-regression analyses were used to compare estimates by study and patient characteristics. Identified were 16 studies, 15 published and 1 unpublished. There was no evidence of publication bias, but there was substantial evidence of heterogeneity, thus precluding reliance on a meaningful summary effect estimate. Meta-regression identified several patient and study characteristics, with some evidence of association with study-specific estimates. None of these characteristics, however, formed subsets of studies with results that were homogeneous enough to aggregate. Research on N-acetylcysteine and the incidence of radiocontrast nephropathy is too inconsistent at present to warrant a conclusion on efficacy or a recommendation for its routine use. Identified patient and study characteristics may be responsible for some, but not all, of this inconsistency. A large, randomized, placebo-controlled trial, a pooled analysis of patient-level data, or both may resolve this issue.

One in four people may develop symptomatic hip osteoarthritis in his or her lifetime

OBJECTIVE To estimate the lifetime risk of symptomatic hip osteoarthritis (OA). DESIGN We analyzed data from the Johnston County Osteoarthritis Project [a longitudinal population-based study of OA in North Carolina, United States (n=3068)]. The weighted baseline sample comprised 18% blacks and 54% women, and the mean age was 63 years (range=45-93). Symptomatic hip OA was defined as a Kellgren-Lawrence (K-L) radiographic score of ≥ 2 (anterior-posterior pelvis X-rays) and pain, aching or stiffness on most days, or groin pain, in the same hip. Lifetime risk, defined as the proportion who developed symptomatic hip OA in at least one hip by age 85, among people who live to age 85, was modeled using logistic regression with repeated measures (through generalized estimating equations). RESULTS Lifetime risk of symptomatic hip OA was 25.3% [95% confidence interval (CI)=21.3-29.3]. Lifetime risk was similar by sex, race, highest educational attainment, and hip injury history. We studied lifetime risk by body mass index (BMI) in three forms: at age 18; at baseline and follow-up; and at age 18, baseline and follow-up and found no differences in estimates. CONCLUSION The burden of symptomatic hip OA is substantial with one in four people developing this condition by age 85. The similar race-specific estimates suggest that racial disparities in total hip replacements are not attributable to differences in disease occurrence. Despite increasing evidence that obesity predicts an increased risk of both hip OA and joint replacement, we found no association between BMI and lifetime risk.

Can one assess whether missing data are missing at random in medical studies

For handling missing data, newer methods such as those based on multiple imputation are generally more accurate than older ones and entail weaker assumptions. Yet most do assume that data are missing at random (MAR). The issue of assessing whether the MAR assumption holds to begin with has been largely ignored. In fact, no way to directly test MAR is available. We propose an alternate assumption, MAR+, that can be tested. MAR+ always implies MAR, so inability to reject MAR+ bodes well for MAR. In contrast, MAR implies MAR+ not universally, but under certain conditions that are often plausible; thus, rejection of MAR+ can raise suspicions about MAR. Our approach is applicable mainly to studies that are not longitudinal. We present five illustrative medical examples, in most of which it turns out that MAR+ fails. There are limits to the ability of sophisticated statistical methods to correct for missing data. Efforts to try to prevent missing data in the first place should therefore receive more attention in medical studies than they have heretofore attracted. If MAR+ is found to fail for a study whose data have already been gathered, extra caution may need to be exercised in the interpretation of the results.

Provider Demonstration and Assessment of Child Device Technique During Pediatric Asthma Visits

OBJECTIVE: The purposes of this study were to (a) describe the extent to which children use metered dose inhalers, turbuhalers, diskuses, and peak flow meters correctly, and (b) investigate how often providers assess and demonstrate use of metered dose inhalers, turbuinhalers, diskuses, and peak flow meters during pediatric asthma visits. PATIENTS AND METHODS: Children ages 8 through 16 with mild, moderate, or severe persistent asthma and their caregivers were recruited at 5 pediatric practices in nonurban areas of North Carolina. All of the medical visits were audiotape-recorded. Children were interviewed after their medical visits, and their device technique was observed and rated by the research assistants. RESULTS: Of the patients, 296 had useable audiotape data. Only 8.1% of children performed all of the metered dose inhaler steps correctly. Older children were more likely to get more of the metered dose inhaler steps correct. Of the children, 22% performed all of the diskus steps correctly, 15.6% performed all of the turbuhaler steps correctly, and 24% performed all of the peak flow meter steps correctly. The majority of providers did not demonstrate or assess child use of metered dose inhalers, turbuhalers, diskuses, or peak flow meters during pediatric asthma visits. CONCLUSIONS: There is a need for providers to demonstrate proper asthma medication and monitoring device techniques to children and to have children demonstrate to proficiency. The 2007 National Heart, Lung, and Blood Institute expert panel report on the diagnosis and management of asthma encourages providers to educate children on these techniques.

Review of nonparametric methods for the analysis of crossover studies.

This paper reviews nonparametric methods for the analysis of crossover studies. Primary attention is given to crossover studies to compare two treatments for a response variable that has a metric measurement level. For this situation, one can often test hypotheses or obtain confidence intervals for parameters of interest by applying well known univariate nonparametric rank methods (e.g., the Wilcoxon rank sum test, or the Wilcoxon signed rank test) to appropriately specified functions of the data. Related extensions are also available, to some degree, for crossover studies to compare more than two treatments or those for which the measurement level of the response variable is ordinal or has a censored time-to-event nature. Methods for several specific situations along these lines are discussed in terms of principles with potentially broader applicability. Several examples are provided to illustrate the performance of some of the methods.

Efficacy of Abciximab readministration in coronary intervention

Abciximab, an Fab monoclonal antibody fragment that blocks the platelet glycoprotein IIb/IIIa receptor, is increasingly used as an adjunct to coronary intervention. Little is known, however, about the efficacy and safety of readministration of abciximab. This study examined and characterized outcomes of patients receiving abciximab for a second time. From April 1995 to June 1997, 164 consecutive patients were readministered abciximab at our 3 institutions. We retrospectively examined and analyzed in-hospital outcomes in this cohort. The median time to readministration was 95 days. The angiographic success rate of percutaneous intervention was 99.5%. Rates and 95% confidence intervals of in-hospital events were death 2% (0.7% to 6.1%), myocardial infarction 3% (1% to 7%), coronary bypass surgery 0% (0% to 2.2%), and intracranial hemorrhage 2% (0.4% to 5.3%). Severe thrombocytopenia was observed in 4% of patients (1.4% to 7.8%) after readministration. Allergic or anaphylactic reactions were not observed. Major bleeding was associated with excessive concomitant antithrombotic therapy. Patients undergoing readministration of abciximab within 2 weeks of first administration experienced a higher incidence of severe thrombocytopenia (12% vs. 2%, p = 0.046). Thus, abciximab remains clinically efficacious when readministered as an adjunct to percutaneous coronary intervention. However, concomitant heparin administration must be carefully monitored and warfarin therapy should be avoided. Vigilant surveillance for thrombocytopenia should be employed. Reduced dosing may be necessary when abciximab is readministered within days of the initial administration.

Communication During Pediatric Asthma Visits and Self-Reported Asthma Medication Adherence

OBJECTIVE: Our objectives were to examine how certain aspects of provider-patient communication recommended by national asthma guidelines (ie, provider asking for child and caregiver input into the asthma treatment plan) were associated with child asthma medication adherence 1 month after an audio-taped medical visit. METHODS: Children ages 8 through 16 with mild, moderate, or severe persistent asthma and their caregivers were recruited at 5 pediatric practices in nonurban areas of North Carolina. All medical visits were audio-tape recorded. Children were interviewed 1 month after their medical visits, and both children and caregivers reported the child’s control medication adherence. Generalized estimating equations were used to determine if communication during the medical visit was associated with medication adherence 1 month later. RESULTS: Children (n = 259) completed a home visit interview ∼1 month after their audio-taped visit, and 216 of these children were taking an asthma control medication at the time of the home visit. Children reported an average control medication adherence for the past week of 72%, whereas caregivers reported the child’s average control medication adherence for the past week was 85%. Child asthma management self-efficacy was significantly associated with both child- and caregiver-reported control medication adherence. When providers asked for caregiver input into the asthma treatment plan, caregivers reported significantly higher child medication adherence 1 month later. CONCLUSIONS: Providers should ask for caregiver input into their child’s asthma treatment plan because it may lead to better control medication adherence.

Child and caregiver involvement and shared decision-making during asthma pediatric visits.

Objective. The purpose of this study was to examine (1) the extent to which caregivers and children asked asthma management questions during pediatric asthma visits; (2) the extent to which providers engaged in shared decision-making with these caregivers and children; and (3) the factors associated with question asking and shared decision-making. Methods. Children aged 8–16 years with mild persistent asthma, moderate persistent asthma, or severe persistent asthma and their caregivers were recruited at five pediatric practices in non-urban areas of North Carolina. All of the medical visits were audio tape recorded. Generalized estimating equations were used to analyze the data. Results. Only 13% of children and 33% of caregivers asked one or more questions about asthma management. Caregivers were more likely to ask questions about their child’s medications. Providers obtained child input into their asthma management plan during only 6% of encounters and caregiver input into their child’s asthma management plan during 10% of visits. Conclusion. Given the importance of involving patients during healthcare visits, providers need to consider asking for and including child and caregiver inputs into asthma management plans so that shared decision-making can occur more frequently.

Ethnicity and depression treatment preferences of pregnant women

African American, Hispanic, and White women between 12 and 32 weeks gestation were recruited to examine their depression treatment preferences. The 73 women who participated were interviewed after their prenatal visit. Nineteen percent of women had symptoms of moderate or severe depression. Women with moderate or severe symptoms of depression were more likely to believe that antidepressants were an acceptable treatment than those without symptoms or with only minor depression symptoms. There were only small differences among the three ethnic groups for antidepressant use preference but most women found them to be unacceptable. In contrast, approximately half of the White women felt that herbal medicines were acceptable compared with 16 and 22 percent for African Americans and Hispanics, respectively. Only 44 percent of African American women felt that counseling from a mental health professional was an acceptable treatment for depression compared to 68 percent for White and 61 percent for Hispanic women. Similarly, African American women were less likely to believe that waiting and getting over depression symptoms naturally was acceptable compared to Hispanic and White women.