Association between lithium treatment and renal, thyroid and parathyroid function: A cohort study of 6659 patients with bipolar disorder.

OBJECTIVES: Although potential adverse effects of lithium treatment on renal and endocrine systems have been extensively investigated, most prior studies are limited by selected populations and short follow-up. METHODS: Within the Psychiatric Services of the Central Denmark Region, we identified all patients with bipolar disorder and ≥1 serum-lithium (se-Li) measurements between January 1, 2013, and July 20, 2022, and reference patients with bipolar disorder matched on age, sex, and baseline creatinine. Outcomes were diagnoses of renal, thyroid and parathyroid disease, and blood tests measuring creatinine, estimated glomerular filtration rate (eGFR), thyroid-stimulating hormone (TSH), parathyroid hormone (PTH) and calcium. Analyses included unadjusted multilevel regression to describe changes in biochemical markers, and adjusted Cox regression to compare rates of disease/biochemical outcomes between lithium users and reference patients. RESULTS: Among 1646 lithium users (median age 36 years, 63% women) and 5013 reference patients, lithium users had decreasing TSH and eGFR, stable PTH, and increasing calcium levels over time. Lithium use was associated with increased rates of renal, thyroid and parathyroid disease, and levels of biochemical markers outside normal ranges (hazard rate ratios: 1.07-11.22), but the absolute number of severe outcomes was low (e.g., chronic kidney disease: N = 10, 0.6%). Notably, the rate of blood testing was substantially higher among lithium users than among reference patients (e.g., mean number of creatinine tests during the second year of follow-up: lithium users = 2.5, reference patients = 1.4). CONCLUSIONS: Severely adverse renal and endocrine outcomes are rare during lithium treatment. Observational studies of long-term lithium treatment are prone to detection bias.

Clinical validation of the self-reported 6-item Hamilton Depression Rating Scale (HAM-D6-SR) among inpatients.

BACKGROUND: Brief and valid patient-rated symptom scales represent a valuable addition to clinician-rated scales for assessing depression. Studies on the psychometric properties of the self-rated 6-item Hamilton Depression Rating Scale (HAM-D6-SR) have shown promising results for outpatients with depression. The aim of the present study was to evaluate the psychometric properties of the HAM-D6-SR among inpatients using the clinician-rated 17-item Hamilton Rating Scale for Depression (HAMD17) as the gold standard. METHODS: Inpatients with unipolar or bipolar depression completed the HAM-D6-SR and were subsequently rated on the HAM-D17 by trained raters, who were blind to the HAM-D6-SR ratings. The pairs of HAM-D6-SR and HAM-D17 ratings were completed twice during admission to evaluate responsiveness over time. Agreement between the HAM-D6-SR and the clinician-rated HAM-D17-derived HAM-D6 was evaluated using the intraclass correlation coefficient (ICC). Responsiveness was evaluated by means of the Spearman's rank correlation coefficient (rho). RESULTS: A total of 102 participants completed the HAM-D6-SR at least once (median age: 41 years; 66 % females). The ICC for the HAM-D6-SR and the HAM-D17-derived HAM-D6 was 0.60 (95%CI = 0.30-0.76), with the ICC at the item level ranging from 0.13 (Psychomotor retardation) to 0.75 (Depressed mood). The correlation between the changes in the baseline-endpoint total scores on the HAM-D6-SR and HAM-D17-derived HAM-D6 was rho = 0.59 (p < 0.001). LIMITATIONS: Test-retest reliability and structural validity were not evaluated. CONCLUSIONS: The HAM-D6-SR holds promise as a valid self-report of core depressive symptoms among inpatients and may aid treatment decisions. However, the validity of self-reported psychomotor retardation was poor.