Validation of administrative data to estimate vaccine impact: Audit of the Fiji hospital admissions electronic database, 2007–2011 & 2014–2015

Objectives Post-licensure studies to evaluate vaccine impact are an important component of introducing new vaccines. Such studies often rely on routinely collected data but the limitations to these data must be understood. To validate administrative data for use in 10-valent pneumococcal conjugate and rotavirus vaccine impact evaluations we have audited the two electronic database capturing hospital admissions in Fiji for completeness and consistency. Methods Hospital admission data for one week per year between 2007–2011 and 2014–2015 was collected from ward registers for selected hospitals. Ward registers were defined as the reference standard and compared to data captured in electronic databases. Data quality was assessed for completeness of admissions data (percentage of admissions in the electronic database, expressed as sensitivity), consistency of complete reporting (determined by identifying variables associated to complete reporting), and completeness of coding (percentage of admissions in the electronic database with an assigned ICD-10-AM code). Results Over all hospitals and years, the sensitivity for completeness of admission data was 83% (95% CI: 81.3, 84.6). Consistency of complete reporting varied and was highest at tertiary hospitals using the electronic database (sensitivity: 89.1%, 95% CI: 87.4, 90.7). The overall completeness of coding at tertiary hospitals was 90.8% (95% CI: 90.5, 91.1) with annual and hospital variation. Conclusion The administrative data in the electronic databases in Fiji are of reasonable quality for the vaccine impact evaluation. This quantification of the missing data can be used to adjust the vaccine impact estimates.