Development and validation of an acceptability and satisfaction questionnaire for a contraceptive vaginal ring, NuvaRing.
Author(s): Novak A, de la Loge C, Abetz L
Affiliation(s): N.V. Organon, Oss, The Netherlands.
Publication date & source: 2004, Pharmacoeconomics., 22(4):245-56.
OBJECTIVE: To validate an acceptability questionnaire for NuvaRing, a new combined contraceptive vaginal ring. METHODS: A 21-item questionnaire was developed covering: ease of ring use, ease of package use, clarity of instructions, sexual comfort, cycle-related characteristics, compliance and satisfaction. A total of 2145 women completed the questionnaire after 3, 6 or 13 cycles of NuvaRing use. The psychometric properties and predictive value of the questionnaire were assessed using cycle 3 data (n = 1950). The quality of completed questionnaires, item content analysis, construct validity, internal consistency reliability, known groups validity and predictive validity were evaluated. RESULTS: Excluding non-ordinal items, 0.6% of the data were missing. Principal component analysis of 15 ordinal items indicated that two hypothesised dimensions ('ease of package use' and 'clarity of instructions') were consistently linked and so were combined into a single 'ease of comprehension' scale. Item convergent validity (the degree of correlation between an item and its own scale) was 100% for 'ease of ring use' (r = 0.44) and 'satisfaction' (r = 0.58), 83% for 'ease of comprehension' (r = 0.25-0.62) and 67% (r = 0.38-0.54) for 'sexual comfort', but 0% for 'cycle-related characteristics' (r = 0.31). Item discriminant validity (the degree to which an item correlates with its own scale compared with other scales) was >/=96% for all dimensions. Internal consistency reliability was acceptable for all dimensions (adjusted Cronbach's alpha coefficient >0.70). Satisfaction was higher than in the complementary groups for respondents who had no adverse events, chose NuvaRing as the best method of contraception or completed the study; this indicated good known groups validity. Low satisfaction with the method was a good predictor of early discontinuation after cycle 3, indicating that the questionnaire had good predictive validity. CONCLUSIONS: The acceptability questionnaire has good psychometric properties and can predict early discontinuation of the NuvaRing vaginal ring method of contraception.