Leptospirosis and Depression: A Nationwide Cohort Analysis.

OBJECTIVE

We conducted a retrospective cohort study to investigate whether leptospirosis is a risk factor for depression.

METHOD: From the Taiwan National Health Insurance Research Database between 2000 and 2010, patients with leptospirosis (ICD-9 code 100) who did not have a history of depression (ICD-9-CM codes 296.2, 296.3, 300.4, and 311) before the index date were enrolled (leptospirosis cohort). For each patient with leptospirosis, 1 control without a history of leptospirosis and depression was randomly selected (nonleptospirosis cohort). Cox proportional hazards regression models were used to analyze the risk of depression according to sex, age, and comorbidities.

RESULTS

In the leptospirosis and nonleptospirosis cohorts, we observed 34 patients with depression, with the incidence rate of 2.87 per 1,000 person-years, and 25 patients with depression, with the incidence rate of 1.93 per 1,000 person-years, respectively, yielding a crude hazard ratio (HR) of 1.49 (95% confidence interval [CI], 1.25-1.77) and an adjusted HR (aHR) of 1.58 (95% CI, 1.34-1.88). Compared with the nonleptospirosis cohort, the leptospirosis cohort had a risk of depression stratified by sex, age, and comorbidity that was higher in female patients (aHR = 2.08; 95% CI, 1.54-2.80), patients younger than 49 years old (aHR = 3.19; 95% CI, 2.39-4.27), and patients without comorbidity (aHR = 2.14; 95% CI, 1.68-2.71). The risk of depression was higher in women than in men (aHR = 1.90; 95% CI, 1.61-2.25) and in patients with comorbidities, namely hyperlipidemia (aHR = 1.80; 95% CI, 1.40-2.31), coronary artery disease (aHR = 2.47; 95% CI, 1.96-3.12), stroke (aHR = 1.77; 95% CI, 1.39-2.24), and septicemia (aHR = 2.06; 95% CI, 1.64-2.58).

CONCLUSIONS

Patients with leptospirosis have a 1.58-fold higher risk of depression than that in the general population. Physicians should be alert to the emotional condition and depression symptoms of people who had been suffering from leptospirosis.