Cross-validation of an algorithm detecting acute gastroenteritis episodes from prescribed drug dispensing data in France: comparison with clinical data reported in a primary care surveillance system, winter seasons 2014/15 to 2016/17

Abstract

Background: This study compares an algorithm to detect acute gastroenteritis (AG) episodes from drug dispensing data to the validated data reported in a primary care surveillance system in France.

Methods: We used drug dispensing data collected in a drugstore database and data collected by primary care physicians involved in a French surveillance network, from season 2014/15 to 2016/17. We used an adapted version of an AG discrimination algorithm to identify AG episodes from the drugstore database. We used Pearson's correlation coefficient to evaluate the agreement between weekly AG signals obtained from the two data sources during winter months, in the overall population, by specific age-groups and by regions.

Results: Correlations between AG signals for all ages were 0.84 [95%CI 0.69; 0.92] for season 2014/15, 0.87 [95%CI 0.75; 0.93] for season 2015/16 and 0.94 [95%CI 0.88; 0.97] for season 2016/17. The association between AG signals estimated from two data sources varied significantly across age groups in season 2016/17 (p-value < 0.01), and across regions in all three seasons studied (p-value < 0.01).

Conclusions: There is a strong agreement between the dynamic of AG activity estimated from drug dispensing data and from validated primary care surveillance data collected during winter months in the overall population but the agreement is poorer in several age groups and in several regions. Once automated, the reuse of drug dispensing data, already collected for reimbursement purposes, could be a cost-efficient method to monitor AG activity at the national level.

Keywords: Epidemiology; Gastroenteritis; Pharmacy; Primary care physicians; Public health surveillance; Sentinel surveillance.

Fig. 1

Identification of acute gastroenteritis episodes among prescriptions containing drugs used in the treatment of acute gastroenteritis, according to the discrimination algorithm applied on drug dispensing data available in the LTD database, seasons 2014/15 to 2016/17 (week number 36 of year N to week number 15 of year N + 1)

Fig. 2

Weekly number of acute gastroenteritis episodes estimated from drug dispensing data using the discrimination algorithm vs. weekly incidences of acute gastroenteritis estimated at the French Sentinelles Network, in the overall population, seasons 2014/15 to 2016/17 (week number 36 of year N to week number 15 of year N + 1)

Fig. 3

Weekly number of acute gastroenteritis episodes estimated from drug dispensing data using the discrimination algorithm vs. weekly incidences of acute gastroenteritis estimated at the French Sentinelles Network, per age groups, seasons 2015/16 and 2016/17 (week number 36 of year N to week number 15 of year N + 1)