Impact of source data verification on data quality in clinical trials: an empirical post hoc analysis of three phase 3 randomized clinical trials.

AIM: The aim of this project was to perform an empirical evaluation of the impact of on site source data verification (SDV) on the data quality in a clinical trial database to guide an informed decision on selection of the monitoring approach. METHODS: We used data from three randomized phase III trials monitored with a combination of complete SDV or partial SDV. After database lock, individual subject data were extracted from the clinical database and subjected to post hoc complete SDV. Error rates were calculated with focus on the degree of on study monitoring and relevance and analyzed for potential impact on end points. RESULTS: Data from a total of 2566 subjects including more than 3 million data fields were 100% source data verified post hoc. An overall error rate of 0.45% was found. No sites had 0% errors. 100% SDV yielded an error rate of 0.27% as compared with partial SDV having an error rate of 0.53% (P < 0.0001). Comparing partly and fully monitored subjects, minor differences were identified between variables of major importance to efficacy or safety. CONCLUSIONS: The findings challenge the notion that a 0% error rate is obtainable with on site monitoring. Data indicate consistently low error rates across the three trials analyzed. The use of complete vs. partial SDV offers a marginal absolute error rate reduction of 0.26%, i.e. a need to perform complete SDV of about 370 data points to avoid one unspecified error and does not support complete SDV as a means of providing meaningful improvements in data accuracy.

Late-Life Risk Factors for All-Cause Dementia and Differential Dementia Diagnoses in Women: A Prospective Cohort Study.

Since the first evidence of a decline in dementia incidence was reported in 2011, the focus on modifiable risk factors has increased. The possibility of risk factor intervention as a prevention strategy has been widely discussed; however, further evidence in relation to risk factors is still needed. The Prospective Epidemiologic Risk Factor (PERF I) study was an observational prospective study of postmenopausal Danish women who were initially examined between 1999 and 2001 (n = 5855). Follow-up data on diagnosis and survival as of December 31, 2014 was retrieved from the National Danish Patient Registry and the National Danish Causes of Death Registry. Cox proportional hazards regression model was applied to calculate adjusted hazard ratios (HR) for selected risk factors for dementia. Of 5512 eligible subjects, 592 developed dementia within the follow-up period of maximum 15 years. The independent factors associated with increased risk of all-cause dementia were depression (HR = 1.75 [95% CI 1.32-2.34]) and impaired fasting glucose levels. A dose-response relationship was observed between fasting glucose level and risk of dementia with HRs of 1.25 [1.05-1.49] and 1.45 [1.03-2.06] for impaired (5.6-6.9 mmol/L) and hyperglycemic (≥7.0 mmol/L) glucose levels, respectively. The factors associated with a decreased risk of dementia were overweight in late-life (HR = 0.75 [0. 62-0.89]) and physical activity at least once weekly (HR = 0.77 [0.61-0.96]). The identified risk factors for dementia in women in late-life are all considered modifiable. This supports the notion that prevention strategies may improve the poor future prospects for dementias in the ageing population.

Two to three years of hormone replacement treatment in healthy women have long-term preventive effects on bone mass and osteoporotic fractures: the PERF study.

Hormone replacement therapy (HRT) is often prescribed for a few years to suppress menopausal symptoms. Although its long-term use of HRT for the primary prevention of osteoporosis is not currently recommended, the long-term skeletal benefits of the limited therapy are of great interest. To determine whether administration of HRT for 2-3 years in the early postmenopausal years provides long-term benefits, such as prevention of bone loss and osteoporotic fractures, we studied a group of 347 healthy postmenopausal women with normal bone mass who had earlier completed one of four placebo-controlled HRT trials and who were reexamined 5, 11, or 15 years after stopping HRT. Of these women, 263 received either HRT or placebo for 2-3 years with no further bone-sparing treatment until follow-up, and the remaining 84 women reported either prolonged or current use of HRT at reexamination. Bone mineral density (BMD) at the spine (L1-L4) and bone mineral content (BMC) in the forearm were measured at baseline, the end of the trials, and follow-up. At follow-up, we assessed the radiological presence of vertebral fracture and collected information on the new incidence of nonvertebral fractures. Compared with that of the placebo-treated women, the BMD and BMC of HRT-treated women continued to show significantly higher values (>5%) even many years after stopping HRT. After stopping treatment, the rate of bone loss returned to normal postmenopausal rates. The preservation of bone mass in the HRT group was accompanied by a significantly reduced risk of all osteoporotic fractures as compared with the placebo group [OR = 0.48 (95% CI, 0.26-0.88)]. 'Fast losers' on placebo had more than a 4-fold higher risk of fractures than had the women on limited HRT with a normal rate of bone loss after withdrawal. In conclusion, limited HRT administered in the early postmenopausal years offers long-lasting benefits for the prevention of postmenopausal bone loss and osteoporotic fracture.