Second-generation antipsychotic medications and risk of chronic kidney disease in schizophrenia: population-based nested case–control study

OBJECTIVES: The study aims to compare the risk of chronic kidney diseases (CKDs) between patients with schizophrenia using first and second-generation antipsychotics. SETTING: Datasets of 2000–2013 National Health Insurance in Taiwan were used. PARTICIPANTS: The National Health Insurance reimbursement claims data have been transferred to and managed by the National Health Research Institute in Taiwan since 1996. We used the Psychiatric Inpatient Medical Claims database, a subset of the National Health Insurance Research Database, comprising a cohort of patients hospitalised for psychiatric disorders between 2000 and 2013 (n=2 67 807). The database included patients with at least one psychiatric inpatient record and one discharge diagnosis of mental disorders coded by the International Classification of Diseases, Ninth Revision (ICD-9) codes 290–319. The age of patients at first admission was restricted to 18–65 years. PRIMARY OUTCOME: CKD (ICD-9 code 582, 583, 585, 586, 588) requiring hospitalisation or three outpatient visits. The diagnosis of CKD follows the criteria of ‘Kidney Disease: Improving Global Outcomes’ in Taiwan. CKD is defined as a kidney damage as albumin-to-creatinine ratio >30 mg/g in two of three spot urine specimens or glomerular filtration rate <60 mL/min/1.73 m(2) for 3 months or more. RESULTS: We found that the risks for CKD were higher for those who used second-generation antipsychotics (SGAs) longer cumulatively than those who did not. Using non-users, patients did not have any SGA records, as reference group, the risks for CKD comparing those using SGAs for 90 to 180 days with non-users and those using SGAs for more than 1000 days were 1.42 (1.06–1.91) and 1.30 (1.13–1.51), respectively. CONCLUSIONS: The current study suggests the relationship between using SGAs and risk of CKD.