Objective: To evaluate the contribution of hospital-to-hospital variability in changes in clinical and health-related quality of life outcomes among patients undergoing cataract extraction by phacoemulsification.
Methods: Prospective observational study of 14 public hospitals. We recruited consecutive patients on waiting lists for cataract extraction. Clinical data were collected prior to the intervention and 6 weeks afterward. Subjects completed the visual function index (VF-14) prior to the procedure and 3 months afterward. Univariate and multivariate analysis were performed for visual acuity and VF-14 scores.
Results: Substantial differences were observed across the 14 hospitals. At baseline, mean visual acuity ranged from 0.16 to 0.34, and mean VF-14 scores ranged from 48.06 to 75.89. Following cataract extraction, the mean improvement in visual acuity ranged from 0.35 to 0.57 and in VF-14 scores from 10.94 to 41.70. The ranges were even more pronounced among patients with low visual acuity or low VF-14 scores prior to the intervention. Significant differences remained in multivariate analysis. Within the multivariate analysis, the variable 'hospitals' had an R(2) of 0.069 for the visual acuity model and of 0.073 for the VF-14 model, 20% and 13%, respectively, of the total variability explained. Variation was also observed within geographic regions.
Conclusions: Outcomes of patients undergoing cataract extractions vary widely from hospital to hospital, even within the same geographic region, explaining an important part of the results. Quality improvement efforts should concentrate on patients with low pre-intervention visual acuity or vision-related disability to reduce this variability in outcomes.