Table 4.
Health-related quality of life Data estimates based on SF-36 RAND responses | |||||||
Control group | Intervention group | Difference | p Value | Test | |||
Health utility index | n | Mean (SD) | n | Mean (SD) | Mean (SE) | ||
Utility at baseline | 64 | 0.656 (0.109) | 64 | 0.643 (0.108) | −0.012 (0.019) | 0.521 | t-test |
Utility at 3 months | 64 | 0.680 (0.114) | 57 | 0.683 (0.108) | 0.003 (0.020) | 0.869 | t-test |
Utility at 6 months | 62 | 0.678 (0.120) | 57 | 0.687 (0.106) | 0.008 (0.020) | 0.684 | t-test |
QALY (AUC) | 55 | 0.340 (0.051) | 47 | 0.342 (0.045) | 0.003 (0.009) | 0.776 | t-test |
QALY difference (controlling for baseline utility) | 55 | 47 | 0.006 (0.006) | 0.286 | OLS regression (white adjusted SE) |
Utility index scores calculated at a patient level, from SF-36, reduced to SF-6D using published utility weights.25 Quality of life (area under curve) estimated as the time integral of the utility scores over the 6-month trial period; quality of life difference estimated parametrically using ordinary least squares, controlling for baseline utility score.
AUC, area under the curve; SF-36, Short Form-36; QALY, quality-adjusted life years.