Background: Quality of Life (QoL) studies concerns the difference in QoL between the baseline and the post-surgical assessment. Many such studies, however, suffer from incomplete QoL-data with regard to patients with a proven survival--the drop-outs. Our hypothesis is that patients with a low preoperative QoL, high operative risk and older age are at higher risk for drop-out, which may result in a biased conclusion.
Methods: This study includes 1675 patients, all of whom were operated between July 1, 2009 and July 1,2012 and have a proven one-year survival, as well as a complete preoperative EuroQoL registration (EQ-5D and EQ-VAS). Based on the calculated 30 and 70 percentiles of age, EuroSCORE risk, and EQ-5D and EQ-VAS values, the group was split into three different subgroups. We studied whether (1) there was a correlation between age, risk, preoperative QoL and postoperative QoL and (2) if the drop-outs were correlated to age, risk and preoperative QoL.
Results: There is a statistically significant correlation between postoperative QoL and both age (p = 0.029) and risk (p = 0.002). Both relations have a negative Pearson's r. There is also a statistically significant (p = 0.0001) correlation between pre- and postoperative QoL, now with a positive Pearson's r. The percentage of drop-outs increases in a statistically significant manner with an increased risk (p = 0.001), older age (p = 0.001) and a low preoperative QoL (EQ-5D, p = 0.001 and EQ-VAS, p = 0.003).
Conclusion: We conclude that QoL post cardiac surgery is overestimated, certainly for older, high risk patients and patients with a low preoperative QoL.