Analysis of quality of life data from a randomized, placebo-controlled heart-failure trial

In a randomized, double-blind, placebo-controlled, 3-months trial involving 111 congestive heart failure patients, one non-validated and three validated Quality of Life (QL) instruments were administered. Two randomized treatment groups were evaluated, one with 62 patients who continued on standard therapy and the other with 49 patients whose standard therapy was replaced by placebo. The data from Patient's Self-rating Scale (a non-validated instrument) and Spitzer's QL index showed a significant difference between the two treatment groups for an overall effect. There were no significant differences between two treatment groups for Sickness Impact Profile (SIP) and Quality of Well-Being (QWB). For analyzing the multiple components in a QL instrument, the global statistics as suggested by O'Brien were applied to compare the two treatment groups. Univariate statistics complemented the global methods. The general use of global statistics in analyzing QL data is recommended.