Recall of drug utilization depends on subtle structural questionnaire characteristics

To test the hypothesis that questionnaire organization affects the recall of antimalarial drugs utilization. Setting Maputo, Mozambique.

Treatment of last malaria episode was assessed using two alternative versions (A and B) of a questionnaire, which differed only by the order each proposed drug was presented in the response options (version A: quinine and most frequently used drugs presented first; version B: less frequently used drugs first and quinine at the end). Questionnaires A or B were randomly assigned to each of 32 classes in a private University in Maputo, Mozambique. Within each classroom all subjects received the same questionnaire version, and a similar number of participants fulfilled questionnaires A (n = 249) and B (n = 255). Main outcome measures Recall of the antimalarial drugs utilization in a previous malaria episode.

Mefloquine and clindamycin were not used by any subject in the last malaria episode. The overall recall of quinine utilization was higher with questionnaire A (19.5% vs. 11.6%, P = 0.006) and the use of artemisinine/artesunate was reported more frequently by subjects inquired with questionnaire B (16.5% vs. 7.3%, P = 0.012). When considering subjects reporting more than one malaria episode, the recall of quinine utilization was higher with questionnaire A (20.0% vs. 6.4%, P = 0.004), and the use of artemisinine/artesunate was reported more frequently by subjects inquired with questionnaire B (18.3% vs. 8.8%, P = 0.069). No differences were observed among those having had only one malaria episode, neither for quinine (22.2% vs. 20.0%, P = 0.807) or artemisinine/artesunate (5.0% vs. 6.7%, P = 0.701).

The structure of the questionnaire used to collect self-reported information about antimalarial treatments influences the recall, even when close ended questions asking for specific drugs are used. Among subjects having been treated for malaria more than once, the first antimalarial drugs being asked were more likely to be selected.