Functional prognosis of older adults with tetanus in Japan: a single-center retrospective study

Globally tetanus causes 26,000-48,000 deaths annually, mostly in children in lower and middle-income countries. In Japan, approximately 100 cases of tetanus are diagnosed annually, mostly in older adults. However, information on the functional prognosis of tetanus in older adults in high-income countries is limited. Therefore, this study assessed the functional prognosis of adults hospitalized with tetanus in Japan.

We retrospectively reviewed the medical records of patients admitted to our hospital with tetanus between January 2000 and June 2025. Data were collected on patient medical history, vital signs, laboratory test results, treatment, and outcomes. Activities of daily living (ADL) were assessed before admission, on admission, and on discharge using the Barthel Index. A worsening functional prognosis was defined as a decline in the Barthel Index.

Twenty-four patients were diagnosed with tetanus (median age: 72 years, range: 40-96 years). Records were not available on whether the patients had received adequate vaccination. The median hospital stay was 66 days (range: 6-181 days). Of the patients, 88% (21/24) required intensive care unit admission, 75% (18/24) required mechanical ventilation, and 58% (14/24) developed hospital-acquired infections (HAIs). On discharge, 48% (11/23) of the patients showed a functional decline. HAIs and a tetanus severity score ≥ 8 were associated with a greater functional decline.

Almost half of the older adults with tetanus experienced a decline in ADL on discharge. Furthermore, HAI was associated with greater functional decline. These results highlight the importance of tetanus prevention in older adults.