Stillbirth among women prescribed nicotine replacement therapy in pregnancy: analysis of a large UK pregnancy cohort

Objective: To compare risk of stillbirth between maternal smokers and those prescribed NRT during pregnancy. Design: Cross-sectional analysis nested in a pregnancy cohort with longitudinal routinely-recorded medical data. Setting: United Kingdom primary care; The Health Improvement Network (THIN) general practice database Population: 220,630 singleton pregnancies ending in live or stillbirth, 2001-2012 Methods: Women were categorised into three groups: NRT (prescribed during pregnancy or one month before conception); smokers; controls (non-smokers without a pregnancy NRT prescription). Main Outcome Measure: odds ratios (OR) adjusted to maternal characteristics and 95% confidence intervals (CIs) for stillbirth Results: A total of 805 pregnancies ended in stillbirth (3.6/1,000 births). Absolute risks of stillbirth in NRT and smoker groups were both 5/1,000 births compared with 3.5/1,000 births in the control group. Compared with the control group, the adjusted odds of stillbirth in the NRT group was not statistically significant (OR=1.35, 95% CI 0.91-2.00), although it was similar in magnitude to that in the smokers group (OR=1.41, 95% CI 1.13-1.77). Conclusions: We found no evidence of a statistically significant association between being prescribed NRT during pregnancy and odds of stillbirth compared with non-smoking women. Although our study had much larger numbers than any previously, an even larger study with biochemically-validated smoking outcome data and close monitoring of NRT use throughout pregnancy is required to exclude effects on findings of potential exposure misclassification

The Limited Incorporation of Economic Analyses in Clinical Practice Guidelines

BACKGROUND: Because there is increasing concern that economic data are not used in the clinical guideline development process, our objective was to evaluate the extent to which economic analyses are incorporated in guideline development. METHODS: We searched medline and HealthSTAR databases to identify English-language clinical practice guidelines (1996–1999) and economic analyses (1990–1998). Additional guidelines were obtained from The National Guidelines Clearinghouse Internet site available at . Eligible guidelines met the Institute of Medicine definition and addressed a topic included in an economic analysis. Eligible economic analyses assessed interventions addressed in a guideline and predated the guideline by 1 or more years. Economic analyses were defined as incorporated in guideline development if 1) the economic analysis or the results were mentioned in the text or 2) listed as a reference. The quality of economic analyses was assessed using a structured scoring system. RESULTS: Using guidelines as the unit of analysis, 9 of 35 (26%) incorporated at least 1 economic analysis of above-average quality in the text and 11 of 35 (31%) incorporated at least 1 in the references. Using economic analyses as the unit of analysis, 63 economic analyses of above-average quality had opportunities for incorporation in 198 instances across the 35 guidelines. Economic analyses were incorporated in the text in 13 of 198 instances (7%) and in the references in 18 of 198 instances (9%). CONCLUSIONS: Rigorous economic analyses may be infrequently incorporated in the development of clinical practice guidelines. A systematic approach to guideline development should be used to ensure the consideration of economic analyses so that recommendations from guidelines may impact both the quality of care and the efficient allocation of resources