Estimation of lifetime productivity loss from patients with chronic diseases: methods and empirical evidence of end-stage kidney disease from Taiwan.

Objective: Studies that examine the broad allocation of resources, regardless of who bears the costs, should ideally estimate costs from a societal perspective. We have successfully integrated survival rates, employment ratios, and earnings to address the significant challenge of evaluating societal value through productivity assessments of patients with end-stage kidney disease (ESKD) in Taiwan.

Methods: Using a theoretical framework, we interconnected two nationwide databases: the Taiwan National Health Insurance (NHI) and the Taiwan Mortality Registry from 2000 to 2017. Due to the statutory retirement age of 65, we collected data on all patients (83,358) aged 25-64 years diagnosed with ESKD and undergoing maintenance dialysis. We estimated the lifetime survival function through a rolling extrapolation algorithm, which was then combined with the monthly employment ratio and wages to calculate the lifetime employment duration and productivity up to the legal retirement age of ESKD patients. These were compared with sex-, age-, and calendar year-matched referents to determine the loss of employment duration and productivity of ESKD patients.

Results: ESKD patients experienced a loss of approximately 25-56% in lifetime employment duration and a larger loss of about 32-66% in lifetime productivity after adjustments for different age, sex, and calendar year. The annual productivity loss per male (female) ESKD patient relative to that of the age-and calendar year-matched referent ranges from 75.5% to 82.1% (82.3% to 90.3%). During the periods when they are able to work (over the on-the-job duration) male ESKD patients lose between 34 and 56% of their income, and female ESKD patients lose between 39 and 68% of their income, compared to the age-and calendar year-matched referents. The loss of lifetime productivity is a combination of reduced lifetime employment duration, functional disability, absenteeism, and presenteeism at the workplace. The loss related to presenteeism is implied by the reduced wages.

Conclusions: In addition to the loss of employment duration, we have empirically demonstrated the lifetime loss of productivity in patients with ESKD, also indicating the "presenteeism" resulted from inability to perform their job with full capacity over long-term periods.