Leptospirosis surveillance evaluation in Suratthani Hospital, Suratthani Province, fiscal year 2024

Abstract

Background: In 2024, Suratthani province reported the 10^th highest incidence rate of leptospirosis in the country. However, reported cases in the disease surveillance system (R506 report) were relatively low. Therefore, we conducted the surveillance system evaluation to describe the structure and process of the reporting disease system, assess qualitative and quantitative attributes and provide recommendations for improvement.

Methods: A cross-sectional study was conducted by interviewing stakeholders involved in the surveillance system about the structure, process of the reporting system and qualitative attributes using a self-developed open-ended questionnaire. Analyzed using thematic analysis. Quantitative attributes were assessed by reviewing the medical records of 462 patients in Suratthani hospital from 1 October 2023 to 30 September 2024 who were diagnosed with ICD-10-TM codes of leptospirosis and related diseases. The case definition adapted on definition for communicable diseases surveillance, Thailand, 2020 and diagnosis of physicians.

Results: The surveillance system was not complicated, good stability and usefulness but lacked flexibility. The system had sensitivity of 57.1% (95% Confidence Interval; 95% CI = 44.2-69.6) based on case definition for diseases and 56.9% (95% CI = 44.2-69.6) based on diagnosis of physicians. Cases definition for diseases surveillance who were not reported initially diagnosed other diseases. The positive predictive value was 12.1% (95% CI = 0.9-23.3) based on surveillance definitions and 100.0% (95% CI = 100.0-100.0) based on diagnosis of physicians. Cases that did not meet the definition but had been reported diagnosis of physicians, but their symptoms and exposure to pathogen were incompletely recorded. The surveillance system showed limitations in representativeness. The timeliness of the surveillance system within 7 days was 69.7%. The completeness of all studied variables were 100.0%. The accuracy for sex, age and diagnosis date were 100.0%, while for address (district-level) was 57.1%.

Conclusion: The leptospirosis surveillance system in Suratthani hospital was not complicated, good stability and usefulness. However, it lacked flexibility based on surveillance definition. The system had moderate sensitivity but low positive predictive value. Physicians should record specific symptoms and history of risk factors completely. If a diagnosis is changed to a surveillance disease should be notified to epidemiologists.