QALY as evaluation tool in a health surveillance program

Quality adjusted life years (QALYs), based on health related quality of life (HRQL), are a commonly used concept in health economics. The aim of this study was to apply the concept of QALY to the evaluation of a surveillance program for health related effects of PCB exposure and measure the impact of occupational PCB-exposure on the remaining QALYs of participants. The internal PCB exposure was determined by gas chromatography with mass spectrometry in plasma. The HRQOL was assessed via the EQ-5D-3L instrument and combined with the remaining lifetime (RLE) at the time point of cessation of exposure. For comparative reasons we used both the linear calculation and the complex-number-model from Prieto and Sacristan. The impact of several PCB congeners was regressed on the percentage of discounted QALYs on RLE via hierarchical multiple regression, controlling for gender, relational and educational status. Findings were able to detect a small but significant effect of elevated plasma levels of PCB on QALY for the linear calculation and partially for the complex number calculation. This means that an internal exposure to PCB reduced HRQOL in the RLE of participants in the surveillance program. QALYs can be applied successfully to monitor HRQL effects in surveillance programs. The exposure to a hazardous substance has an influence on QALYs. Findings have to be interpreted as a first hint. In the following assessment it has to be monitored whether there is an improvement or worsening of HRQL.