Using a discrete choice experiment to value the QLU-C10D: feasibility and sensitivity to presentation format.

PURPOSE: To assess the feasibility of using a discrete choice experiment (DCE) to value health states within the QLU-C10D, a utility instrument derived from the QLQ-C30, and to assess clarity, difficulty, and respondent preference between two presentation formats. METHODS: We ran a DCE valuation task in an online panel (N = 430). Respondents answered 16 choice pairs; in half of these, differences between dimensions were highlighted, and in the remainder, common dimensions were described in text and differing attributes were tabulated. To simplify the cognitive task, only four of the QLU-C10D's ten dimensions differed per choice set. We assessed difficulty and clarity of the valuation task with Likert-type scales, and respondents were asked which format they preferred. We analysed the DCE data by format with a conditional logit model and used Chi-squared tests to compare other responses by format. Semi-structured telephone interviews (N = 8) explored respondents' cognitive approaches to the valuation task. RESULTS: Four hundred and forty-nine individuals were recruited, 430 completed at least one choice set, and 422/449 (94 %) completed all 16 choice sets. Interviews revealed that respondents found ten domains difficult but manageable, many adopting simplifying heuristics. Results for clarity and difficulty were identical between formats, but the "highlight" format was preferred by 68 % of respondents. Conditional logit parameter estimates were monotonic within domains, suggesting respondents were able to complete the DCE sensibly, yielding valid results. CONCLUSION: A DCE valuation task in which only four of the QLU-C10D's ten dimensions differed in any choice set is feasible for deriving utility weights for the QLU-C10D.

Endometrial lysosomal enzyme activity in ovulatory dysfunctional uterine bleeding, IUCD users and post-partum women.

The aim of this study was to evaluate the role of lysosomal enzymes in excessively heavy menstruation by comparing women with menorrhagia due to dysfunctional bleeding or intrauterine contraceptive device (IUCD) use with those with normal menstrual periods or with amenorrhoea associated with breastfeeding. This was a prospective cohort investigation of the activity of four endometrial lysosomal enzymes in three contrasting groups: (i) women with ovulatory dysfunctional uterine bleeding and users of intrauterine contraceptive devices; (ii) breastfeeding post-partum women in whom there are long periods of amenorrhoea, particularly in the early months post-partum; and (iii) normal cycling women. It was found that the total activity of lysosomal enzymes, particularly acid phosphatase and N-acetyl-beta-D-glucosaminidase, was markedly elevated (P < 0.001) in IUCD-exposed endometrium, and endometrium from women with dysfunctional uterine bleeding when compared with endometrium from women with a history of entirely normal menstrual periods or that in post-partum breastfeeding women. The activity of alpha-L-fucosidase was moderately elevated in IUCD users (P < 0.05) and ovulatory dysfunctional uterine bleeding (P < 0.05), whereas alphaD-mannosidase activity was elevated in ovulatory dysfunctional uterine bleeding (P < 0.05), but decreased in IUCD users (P < 0.01). No significant differences were observed in the lysosomal enzyme activities of breastfeeding post-partum women and normal cycling women. These results show that total endometrial tissue activity of four lysosomal enzymes was substantially increased throughout the cycle in most circumstances in women with two different causes for increased menstrual bleeding. This suggests a contributory role to the increased bleeding.

Heterogeneity in disease associations.

Associations between polymorphisms and disease are usually detected by comparing phenotype frequencies in affected individuals and controls, usually by the method of Woolf, which also allows assessment of heterogeneity between studies. The risk of reporting a chance spurious association could be reduced if family studies, such as sib comparisons, were carried out at the same time as the original survey, rather than after many surveys have been conducted.