Birthdays as a Risk Factor for Inpatient Psychiatric Hospitalization: A Case-Crossover Study

BACKGROUND: Birthdays are typically a joyous occasion, but they can paradoxically conjure negative feelings, including reflections on failures and underachievement. In this study, we investigated a relationship between admission dates and patients' birthdays. METHODS: Electronic health records from the Dunn Center hospitals were obtained from April 2021 to June 2024. Patients who were 12 to 80 years of age, except for those in competency restoration units, were included in the analysis. Any admissions occurring 2 weeks before and after the patient's birthday were defined as birthday-associated admissions. A case-crossover analysis was employed to examine the plausible temporal relationship between the birthday period and the acute psychiatric hospitalization. A conditional logistic regression model was used to test the odds of birthday-associated admission versus non-birthday-associated admission. Relevant covariates consisted of age, sex, primary diagnosis, and social determinants of health. RESULTS: A total of 17,847 admissions were included. The case-crossover analysis found that patients were approximately twice as likely (OR=2.08, 95% CI=1.89-2.30, P<0.0001) to be admitted 14 days before or after their birthday relative to a 28-day control window randomly selected within each calendar year. Potentially confounding variables, such as age, admission diagnosis, and social determinants of health, showed no difference in the likelihood of admission. CONCLUSIONS: This analysis supports the hypothesis that, for persons with psychiatric disorders, birthdays may represent periods of increased risk/stress that can manifest in increased inpatient psychiatric admissions. With these results, we can supplement education efforts to inform patients, families, and providers to recognize birthdays as a possible risk factor for worsening psychiatric symptoms.