RESUMEN
BACKGROUND: Lithium was known to cause thyroid dysfunction and most commonly subclinical hypothyroidism (SCH). The aim of this study is to determine the prevalence of Lithium associated thyroid dysfunction and to identify risk factors associated with development of SCH in patients receiving Lithium. METHODS: A retrospective cross-sectional study was conducted. Subjects who developed elated thyroid stimulating hormone (TSH) were compared with those who remained euthyroid with Lithium treatment. Logistic regression and survival analysis were applied to identify the significant factors associated with SCH. RESULTS: The prevalence of Lithium associated with SCH was 31.7 %. The significant risk factors associated with increased risk of SCH included being female, higher serum Lithium level, concomitant use of Valproate Sodium and use of antidepressant. Use of depot injection was associated with decreased risk of SCH. CONCLUSIONS: Use of depot and avoidance of Valproate or antidepressant should be taken into account before starting patient on Lithium treatment. Thyroxine replacement should be considered when Lithium associated SCH was identified.