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Biomedical subjects

C L Meinert

Publications and source records attributed to C L Meinert.

At least 19 recordsLinked to original sources
PubMed2006

Factors affecting attrition in a longitudinal study of patients with AIDS.

Anecdotal data have suggested that retention of HIV-infected patients with immune recovery in longitudinal studies may be difficult as they resume normal activities. This study evaluated risk factors for attrition among patients with AIDS in a cohort study in the era of highly active antiretroviral therapy. Patients with AIDS enrolled in the Longitudinal Study of Ocular Complications of AIDS were evaluated every three months with demographic, clinical and laboratory data collected. Lost to follow-up was defined as any patient who missed all study visits and could not be contacted for 12 consecutive months, who had not died and who did not re-enter the study at a later date. Of the 1,052 patients studied, 77 (7.3%) were lost to follow-up (rate = 0.03/person year). In the multivariate analysis, factors associated with attrition were CD4+ T-cell count category (hazard ratio (HR) = 2.03; 95%CI: 1.01, 4.24; P = 0.05 for CD4+ count < or = 50 cells/microL and HR = 1.96; 95%CI: 1.12, 3.40; P = 0.02 for CD4+ count 51-200 cells/microL) and detectable HIV viral load (HR = 1.29; 95%CI: 1.07, 1.53; P < 0.001 for HIV viral load >400 copies/mL). These data suggest that patients with compromised immunologic status are at an increased risk for being lost to follow-up.

Acquired Immunodeficiency Syndrome↗
PubMed2001

Estimation of gender bias in clinical trials.

The perception is that the clinical trials enterprise has been biased in favour of males by devoting a disproportionate effort to males and to the diseases and conditions afflicting them - a perception reinforced by a few high profile male-only heart trials undertaken in the 1970s and 1980s. The perception was sufficient to cause the U.S.A. Congress to enact legislation to require that a clinical trial 'is designed and carried out in a manner sufficient to provide for a valid analysis of whether the variables being studied in the trial affect women ...differently than other subjects in the trial'. Observed effort differentials are based on counts of single-gender trials indexed in MEDLINE and published in U.S. journals. Differentials are compared to those expected using male-female differentials in mortality and years of potential life loss due to mortality before age 65 to estimate effort bias. The ratios of female-only to male-only published trials were 0.53, 0.89 and 0.95 for the decades of 1966-1975, 1976-1985 and 1986-1995, respectively. The expected ratios, if single-gender trials were done in proportion to female-male mortality differentials, would be 0.57, 0.56 and 0.57, respectively. The differences in observed versus expected female to male ratios correspond to a slight excess of male-only trials in the decade of 1966-1975 and to sizeable excesses in female-only trials in the decades of 1976-1985 and 1986-1995. The results do not support the perception that women have been understudied relative to males in clinical trials. Most differentials favour females, whether based on mortality or years of potential life loss due to mortality before age 65 years.

Adult↗
PubMed2001

Photographic measures of cytomegalovirus retinitis as surrogates for visual outcomes in treated patients.

OBJECTIVE: To evaluate photographic measures of cytomegalovirus (CMV) retinitis as surrogate outcomes for changes in vision in patients with CMV retinitis related to the acquired immunodeficiency syndrome. METHODS: Data from 3 clinical trials of CMV retinitis treatments were analyzed. Two photographic assessments of retinitis in eyes involved at baseline were evaluated: progression (lesion border movement > or = 750 microm or occurrence of a new lesion) and change in area of retina involved with retinitis. Vision measures were decline in best-corrected visual acuity and change in visual field. Photographic measures were evaluated as surrogate outcomes based on 4 criteria: (1) association with vision measure; (2) ability to account for treatment-related differences in vision measure; (3) data completeness; and (4) sample size requirements. RESULTS: Data from 1001 involved eyes (666 patients) were analyzed. Progression and change in area involved were predictive of declines in vision measures, accounted for 50% and 66% of the treatment effect on visual field, and were available from 93% and 64% of involved eyes, respectively. Sample size estimates for a clinical trial were smallest with progression as the design outcome. CONCLUSION: Progression and change in area involved met the first and second criteria for surrogate outcomes for visual field loss; a complete evaluation for visual acuity decline was not possible because treatment-related differences were not observed. Progression met the logistical and sample size criteria better than change in area of retina involved with retinitis.

AIDS-Related Opportunistic Infections↗
PubMed2001

Patient notification and follow-up after suspension of treatment protocols. experience from four clinical trials of treatments for AIDS-related CMV retinitis.

We reviewed procedures for and data about patient notification of the suspension of the treatment protocol for four clinical trials. We also examined how data collected after the suspensions were used. All four trials were designed to evaluate treatments for cytomegalovirus retinitis in patients with AIDS and were conducted by the Studies of Ocular Complications of AIDS Research Group. Documentation that patients were notified of the results varied from 62--100% with three of the four studies documenting the process for > or =92% of patients. The median time between the recommendation for protocol suspension and patient notification varied from 7--49 days with three of the four trials at 12 days or fewer. Most of the analyses of data collected after the suspension of the treatment protocol did not focus on comparisons among treatment groups. Although they provided useful information about the long-term outcomes and the nature of the disease, they did not alter the conclusions about safety and efficacy from the randomized portion of the trial. Control Clin Trials 2001;22:62-68

AIDS-Related Opportunistic Infections↗
PubMed2001

Double-masked randomized trial comparing alternate combinations of intraoperative anesthesia and postoperative analgesia in abdominal aortic surgery.

BACKGROUND: Improvement in patient outcome and reduced use of medical resources may result from using epidural anesthesia and analgesia as compared with general anesthesia and intravenous opioids, although the relative importance of intraoperative versus postoperative technique has not been studied. This prospective, double-masked, randomized clinical trial was designed to compare alternate combinations of intraoperative anesthesia and postoperative analgesia with respect to postoperative outcomes in patients undergoing surgery of the abdominal aorta. METHODS: One hundred sixty-eight patients undergoing surgery of the abdominal aorta were randomly assigned to receive either thoracic epidural anesthesia combined with a light general anesthesia or general anesthesia alone intraoperatively and either intravenous or epidural patient-controlled analgesia postoperatively (four treatment groups). Patient-controlled analgesia was continued for at least 72 h. Protocols were used to standardize perioperative medical management and to preserve masking intraoperatively and postoperatively. A uniform surveillance strategy was used for the identification of prospectively defined postoperative complications. Outcome evaluation included postoperative hospital length of stay, direct medical costs, selected postoperative morbidities, and postoperative recovery milestones. RESULTS: Length of stay and direct medical costs for patients surviving to discharge were similar among the four treatment groups. Postoperative outcomes were similar among the four treatment groups with respect to death, myocardial infarction, myocardial ischemia, reoperation, pneumonia, and renal failure. Epidural patient-controlled analgesia was associated with a significantly shorter time to extubation (P = 0.002). Times to intensive care unit discharge, ward admission, first bowel sounds, first flatus, tolerating clear liquids, tolerating regular diet, and independent ambulation were similar among the four treatment groups. Postoperative pain scores were also similar among the four treatment groups. CONCLUSIONS: In patients undergoing surgery of the abdominal aorta, thoracic epidural anesthesia combined with a light general anesthesia and followed by either intravenous or epidural patient-controlled analgesia, offers no major advantage or disadvantage when compared with general anesthesia alone followed by either intravenous or epidural patient-controlled analgesia.

Aged↗
PubMed2000

The refractive status and vision profile: a questionnaire to measure vision-related quality of life in persons with refractive error.

OBJECTIVE/BACKGROUND: To describe the Refractive Status and Vision Profile (RSVP), a questionnaire that measures self-reported vision-related health status (symptoms, functioning, expectations, concern) in persons with refractive error. DESIGN: Cross-sectional study by survey. PARTICIPANTS: The RSVP was self-administered by 550 participants with refractive error (or history of refractive surgery) recruited from five refractive surgery practices and one optometric practice. Information on refraction, uncorrected and best-corrected visual acuity, and history of refractive surgery was obtained from physicians' records. METHODS: Internal consistency, test-retest reliability, agreement with global measures of vision (criterion validity), discriminant validity, content validity, and construct validity (associations of scale scores with patient status variables) were assessed using Cronbach's alpha, Spearman rank correlations, factor analysis, and multitrait analysis. OUTCOME MEASURES: Scores on the overall RSVP scale (S) and on eight RSVP subscales (functioning, driving, concern, expectations, symptoms, glare, optical problems, problems with corrective lenses) were calculated based on 42 items. RESULTS: Cronbach's alpha was 0.92 for S and ranged from 0.70 to 0.93 for RSVP subscales, indicating good internal consistency. Satisfaction with vision was more strongly associated with S than with refractive error or with visual acuity. Individuals with more refractive error had significantly lower (worse) scores for S and for subscales concern, functioning, driving, optical problems, and glare. Scores for S and for subscales concern, functioning, optical problems, and driving remained significantly associated with satisfaction with vision after adjustment for age, gender, corrective lens type, and refractive error. CONCLUSIONS: The RSVP measures a range of visual, functional, and psychologic impacts of refractive error that are likely to be important to patients. The RSVP would be a useful tool for evaluating interventions for correction of refractive error and may be useful for assessing refractive surgery candidates in clinical practice.

Adolescent↗
PubMed2000

Gender representation in trials.

The perception is that women have been understudied relative to men. It has been sufficient to cause Congress to enact legislation to require that a clinical trial must be "designed and carried out in a manner sufficient to provide for a valid analysis of whether the variables being studied in the trial affect women ellipsis differently than other subjects in the trial." We looked for evidence as to whether the perception has a basis in fact by looking at measures of gender-based research effort. Clinical trials, published between 1966 and 1998 in U.S. journals and indexed in MEDLINE, were classified by gender. Reports of trials appearing in five widely circulated medical journals (Annals of Internal Medicine, British Medical Journal, Journal of the American Medical Association, Lancet, and New England Journal of Medicine) in 1985, 1990, and 1995 were retrieved and read to obtain counts of the numbers of males and females represented in trials published in those journals. For reports of trials published in U.S. journals, the percent involving males and females, males only, females only, and those where gender was not specified were 55.2%, 12.2%, 11.2%, and 21.4%, respectively. Counts of males and females represented in the reports of trials appearing in the five aforementioned journals were 355,624 and 550,743, respectively. We did not find evidence of systematic effort bias against females.

Bias↗
PubMed2000

Clinical review 115: effect of thyroxine therapy on serum lipoproteins in patients with mild thyroid failure: a quantitative review of the literature.

The objective of our study was to estimate the expected change in serum lipoprotein concentrations after treatment with T4 in patients with mild thyroid failure (i.e. subclinical hypothyroidism). Our data sources included MEDLINE, between January 1966 and May 1999, and review of references from relevant articles. There were 1,786 published studies identified, 461 abstracts reviewed, 74 articles retrieved, 24 articles evaluated against predetermined entry criteria, and 13 studies systematically reviewed and abstracted. All studies reported serum total cholesterol concentration changes during T4 treatment, 12 reported triglyceride changes, 10 reported high-density lipoprotein (HDL) cholesterol changes, and 9 reported low-density lipoprotein (LDL) cholesterol changes. There were 247 patients in 13 studies. The mean decrease in the serum total cholesterol concentration was -0.20 mmol/L (-7.9 mg/ dL), with a 95% confidence interval of -0.09 to -0.34. The decline in serum total cholesterol was directly proportional to its baseline concentration. Studies enrolling hypothyroid participants receiving suboptimal T4 doses reported significantly larger decreases in serum total cholesterol after thyroid-stimulating hormone normalization than studies enrolling previously untreated individuals with mild thyroid failure [-0.44 mmol/L (-17 mg/dL) vs. -0.14 mmol/L (-5.6 mg/dL), P = 0.05]. The change in serum LDL cholesterol concentration was -0.26 mmol/L (-10 mg/dL), with a 95% confidence interval of -0.12 to -0.41. Serum HDL and triglyceride concentrations showed no change. These results, although based on fewer than 250 patients, suggest that T4 therapy in individuals with mild thyroid failure lowers mean serum total and LDL cholesterol concentrations. The reduction in serum total cholesterol may be larger in individuals with higher pretreatment cholesterol levels and in hypothyroid individuals taking suboptimal T4 doses. There do not seem to be significant effects of T4 on serum HDL or triglyceride concentrations.

Apolipoproteins↗
PubMed1999

Redesign of trials under different enrollment mixes.

A few large multi-centre male-only heart trials done in the 1970s and 1980s have been seen as ill-conceived because they did not include females. The purpose here is to revisit two of those trials and to consider consequences in terms of cost and power had they been designed to include females.

Adult↗
PubMed1998

Clinical trials and treatment effects monitoring.

Treatment effects monitoring is the act of reviewing accumulated data by treatment group to determine whether a trial should continue unaltered. That monitoring is required for any trial where there is a risk of an aggregate form of harm for subjects because of continued use of an inferior treatment or because of failure to use a superior treatment. Institutional review boards (IRBs), in deciding whether to approve such research, require that (when appropriate) there is adequate provision for monitoring the data collected to ensure the safety of subjects. The focus here is on the conditions necessary to satisfy this requirement. The conditions discussed are timeliness of the monitoring, completeness of data for monitoring, competency of monitors, and freedom of monitors to act and recommend as they deem necessary, regardless of the wishes, desires, or dictates of sponsors.

Clinical Trials as Topic↗
PubMed1997

A controlled trial of immunotherapy for asthma in allergic children.

BACKGROUND: Injections of allergens are widely prescribed for patients with asthma, but little is known about the effectiveness of immunotherapy. METHODS: We conducted a double-blind, placebo-controlled trial of multiple-allergen immunotherapy in 121 allergic children with moderate-to-severe, perennial asthma. The children, who required daily medication for their asthma, were randomly assigned to receive subcutaneous injections of either a mixture of up to seven aeroallergen extracts or a placebo. Maintenance injections were continued for 18 months or longer. Medications were adjusted every two to three weeks on the basis of peak flow rates and symptoms. The principal outcome was the daily medication score. Bronchial sensitivity to methacholine (the concentration provoking a 20 percent decrease in the forced expiratory volume in one second [PC20]) was measured twice yearly. RESULTS: The median medication score declined from 5.4 to 4.9 in the immunotherapy group (P<0.001) and from 5.2 to 5.0 in the placebo group (P<0.001), but there was no significant difference between the groups (P>0.6). The number of days on which oral corticosteroids were used was similar in the two groups. Partial or complete remission of asthma occurred in 31 percent of the immunotherapy group and in 28 percent of the placebo group (P>0.5). There was no difference between the groups in the use of medical care, symptoms, or peak flow rates. The median PC20 increased significantly in both groups, but again with no difference between the two groups. CONCLUSIONS: Immunotherapy with injections of allergens for over two years was of no discernible benefit in allergic children with perennial asthma who were receiving appropriate medical treatment.

Adolescent↗
PubMed1997

Results at age 8 years of early intervention for low-birth-weight premature infants. The Infant Health and Development Program.

OBJECTIVE: To reevaluate at age 8 years children who had participated during the first 3 years of life in a randomized clinical trial of special services for low-birthweight (LBW) premature infants. DESIGN: Follow-up of a randomized controlled trial of premature infants (< or = 37 weeks' gestation), stratified by 2 LBW groups (lighter [< or = 2000 g] and heavier [2001-2500 g]) and divided into intervention (n=377) and follow-up only (n=608) groups. SETTING: Eight sites serving diverse populations. PARTICIPANTS: At age 8 years, 874 children were assessed: 336 in the intervention group and 538 in the follow-up only group. INTERVENTION: The 3-year intervention consisted of home visits (birth to 3 years), child development center services (ages 1 to 3 years), and parent group meetings (ages 1 to 3 years). PRIMARY OUTCOME MEASURES: Cognitive functioning (Weschler Intelligence Scale for Children-III; Peabody Picture Vocabulary Test-Revised); academic achievement (Woodcock-Johnson Tests of Achievement-Revised); and parental reports of school performance, behavior (Child Behavior Checklist), and health (Child General Health Survey). RESULTS: At age 8 years, in the entire cohort and in the lighter LBW stratum, the intervention and follow-up only groups were similar on all primary outcome measures. Differences favoring the intervention group were found within the heavier LBW group: full-scale IQ score (4.4 points higher, P=.007), verbal IQ score (4.2 points higher, P=.01), performance IQ score (3.9 points higher, P=.02), mathematics achievement score (4.8 points higher, P=.04), and receptive vocabulary score (6.7 points higher, P=.001). On a physical functioning subscale, the whole intervention group received less favorable ratings, while the lighter LBW intervention group had lower maternal ratings assessing social limitations caused by behavior. CONCLUSION: Although at age 8 years there were modest intervention-related differences in the cognitive and academic skills of heavier LBW premature children, attenuation of the large favorable effects seen at 3 years was observed in both the heavier and lighter LBW groups. This indicates a need to develop additional intervention strategies for LBW premature children that can provide sustained benefits.

Child↗