Biomedical subjects

Anna-Bettina Haidich

Publications and source records attributed to Anna-Bettina Haidich.

4 recordsLinked to original sources

PubMed2005

Mortality in systemic sclerosis: an international meta-analysis of individual patient data.

PURPOSE: Studies on mortality associated with systemic sclerosis have been limited by small sample sizes. We aimed to obtain large-scale evidence on survival outcomes and predictors for this disease. METHODS: We performed a meta-analysis of individual patient data from cohorts recruited from seven medical centers in the United States, Europe, and Japan, using standardized definitions for disease subtype and organ system involvement. The primary outcome was all-cause mortality. Standardized mortality ratios and predictors of mortality were estimated. The main analysis was based only on patients enrolled at each center within 6 months of diagnosis (incident cases). RESULTS: Among 1645 incident cases, 578 deaths occurred over 11,521 person-years of follow-up. Standardized mortality ratios varied by cohort (1.5 to 7.2). In multivariate analyses that adjusted for age and sex, renal (hazard ratio [HR] = 1.9; 95% confidence interval [CI]: 1.4 to 2.5), cardiac (HR = 2.8; 95% CI: 2.1 to 3.8), and pulmonary (HR = 1.6; 95% CI: 1.3 to 2.2) involvement, and anti-topoisomerase I antibodies (HR = 1.3; 95% CI: 1.0 to 1.6), increased mortality risk. Renal, cardiac, and pulmonary involvement tended to occur together (P <0.001). For patients without adverse predictors for 3 years after enrollment, the subsequent risk of death was not significantly different from that for the general population in three cohorts, but was significantly increased in three cohorts that comprised mostly referred patients. Analyses that included all cases in each center (n = 3311; total follow-up: 19,990 person-years) yielded largely similar results. CONCLUSION: Systemic sclerosis confers a high mortality risk, but there is considerable heterogeneity across settings. Internal organ involvement and anti-topoisomerase I antibodies are important determinants of mortality.

Adult↗

PubMed2004

The Gini coefficient as a measure for understanding accrual inequalities in multicenter clinical studies.

OBJECTIVE: Clinical sites participating in multicenter trials may have unequal performance in recruiting subjects. We propose using the Gini coefficient as a quantitative measure of site accrual inequalities. STUDY DESIGN AND SETTING: We evaluated the relationship of this metric to other study characteristics across 166 clinical studies (27,865 subjects) conducted by the AIDS Clinical Trials Group between 1986 and 1999. RESULTS: Overall there was a modest recruitment inequality among clinical centers (mean Gini=0.33). In multivariate modeling, site accrual inequalities were higher when there was more protracted enrollment, and a larger number of sites and were lower in antiretroviral studies than other studies. In long-term studies, the site accrual inequality increased significantly over time (P=0.004). In efficacy trials, a higher Gini coefficient was associated with higher likelihood of the study results being statistically significant (P=0.010). CONCLUSION: The Gini coefficient may be easily and routinely incorporated in the description of the characteristics of a clinical study and may provide insights about its enrollment pattern.

Adult↗

PubMed2003

Late-starter sites in randomized controlled trials.

In a cohort of 14 randomized controlled trials conducted by the Adult AIDS Clinical Trials Group between 1986 and 1999 with a target sample size of >400 (total enrollment 15,531 patients), we evaluated whether "late-starter" sites can make a meaningful contribution to eventual trial accrual. The sites that started recruiting within 5 months from the time the first patient entered the trial were eventually responsible for over 90% of the total enrollment in 11 of the 14 trials. Across the 14 trials, some sites were consistently among the first to start enrollment, whereas others were routinely among the last. The late-starter sites are unlikely to make important contributions to eventual trial enrollment in large clinical trials conducted by groups with a fixed number of sites. Protracting administrative efforts to add more sites many months after a multicenter trial has started may not be useful to trial accrual.

Acquired Immunodeficiency Syndrome↗

PubMed2002

Severity of HIV-associated neuropathy is associated with plasma HIV-1 RNA levels.

OBJECTIVE: To determine if there is an association between plasma HIV-1 RNA levels and severity of HIV-associated distal symmetrical polyneuropathy (DSP). DESIGN: Substudy of AIDS Clinical Trials Group Protocol 291, a double-blind, placebo-controlled study of recombinant human nerve growth factor for the treatment of painful DSP. METHODS: Two-hundred and thirty-six subjects had plasma HIV-1 RNA load assayed at baseline. Mean and maximum neuropathic pain was assessed once daily by the Gracely Pain Scale. Other measures included subjects' global pain assessment and quantitative sensory tests (QST). These values were correlated with baseline HIV-1 RNA levels. RESULTS: Among 168 subjects with detectable plasma HIV-1 RNA, there was a significant correlation between plasma HIV-1 RNA and the severity of maximum and global pain, and toe cooling thresholds. Maximum and global pain assessment correlated with plasma HIV-1 RNA in individuals with detectable viral load (r, 0.162 and 0.194; P = 0.04 and 0.01, respectively). CONCLUSIONS: There is an association between plasma HIV-1 RNA levels and the severity of pain and QST results in HIV-associated DSP. Further studies are needed to determine if aggressive use of antiretroviral drugs, including the use of dideoxynucleosides, may be of benefit to prevent or improve peripheral neuropathy.

Adult↗