Burden of illness attributable to subclinical hypothyroidism in the Spanish population

Abstract

Abstract Introduction Subclinical hypothyroidism (SH) has been associated recently to cardiovascular diseases. However, the loss of health it entails remains unknown. This study has assessed the burden of illness attributable to SH in Spain. Patients and methods Based on the Spanish prevalence data found in international studies, a theoretical model was developed to estimate the Disability Adjusted Life Years (DALYs), years of life lost (YLL) and years lost due to disability (YLD) associated with SH. Prevalence of risk factors, coronary mortality risk and coronary event risk associated with SH were obtained from a review of the literature. An analysis was conducted according to the World Health Organization methodology approach for these studies, using official Spanish sources (hospital discharge records, minimum basic set data [MBSD], inpatient mortality records, etc.). Results In Spain, approximately 2,767,124 people have SH, specifically 1,949,820 with levels of TSH between 4.5 and 6.9 mIU/L (70.5%), 538,988 with levels between 7 and 9.9 mIU/L (19.5%), and 278,317 between 10 and 19.9 mIU/L (10%). These subjects suffer approximately 12,608 cardiac events and 1388 deaths a year attributed to their SH. This represents 30,550 DALYs (13,124 YLL and 17,426 YLD). Between 1.6 and 7.3% of cardiovascular DALYs can be attributed to SH. Conclusion SH is a silent disease which considerably increases the burden of disease. Evaluation of SH, at least in patients belonging to risk groups, could be cost-effective.