Developing a geographic search filter to identify randomised controlled trials in Africa: finding the optimal balance between sensitivity and precision

Abstract

Background: Research on identifying trials using geographic filters is limited. Objectives: To test the sensitivity and precision of a filter to identify African randomised controlled trials (RCTs). Methods: We searched MEDLINE and EMBASE for RCTs published in 2004 using a Cochrane filter for RCTs. The search was limited to HIV ⁄AIDS but irrespective of location. Two investigators independently identified African RCTs from the retrieved records forming a reference set. We then repeated the search using an African geographic filter comprising country and regional terms forming the filter set. We compared the sensitivity and precision of the sets. Results: The MEDLINE reference set comprised 1799 records with 23 African RCTs; for EMBASE, the reference set comprised 763 records with 37 African RCTs. The MEDLINE filter set comprised 180 records with 17 African RCTs; the EMBASE filter set comprised 98 records with 27 African RCTs. Sensitivity of the filter was 74% (MEDLINE) and 73% (EMBASE). Addition of the filter improved precision from 1.3% to 9.4% (MEDLINE) and from 5% to 28% (EMBASE). Conclusion: The African filter improved precision with some loss in sensitivity. Incomplete reporting of trial location in electronic bibliographic records restricts efficiency of geographic filters. Prospective trial registration should alleviate this.

Avoidable waste related to inadequate methods and incomplete reporting of interventions: a systematic review of randomized trials performed in Sub-Saharan Africa

“…We relied on a sample of RCTs that was used in a previous work which aimed to describe the epidemiology of RCTs in SSA [13]. In brief, we searched for all reports of published RCTs indexed in PubMed, the Cochrane Central Register of Controlled Trials (CENTRAL) and the African Index Medicus (AIM) based on the Cochrane Highly Sensitive Search Strategy for identifying randomized trials [14] combined to a geographic search filter to identify RCTs in Africa [15]. The core search string was varied depending on the database (see Additional file 2).…”

Melioidosis in Africa: Should we be Looking more Closely?

“…To provide an overview of the literature on melioidosis in Africa and its public health relevance, we searched the PubMed database (last update in June 2014). The following Mesh terms were used: melioidosis or pseudomallei or Whitmor* combined with the geographic search filter for Africa [19]. The search was limited to studies published in English and French.…”

Effective components of exercise and physical activity-related behaviour-change interventions for chronic non-communicable diseases in Africa: protocol for a systematic mixed studies review with meta-analysis

“…We will search the following African regional databases: African Index Medicus (AIM) and AFROLIB, which is the WHO's regional office database for Africa, until 18 July 2015. The search strategy will be informed by the African search filter, reported to have good sensitivity (74% for Medline and 73% for EMBASE), and improved precision from 1.3% to 9.4% in Medline and from 5% to 28% in EMBASE 31. The African search filter comprises names of each country in Africa, and truncated terms to capture studies indexed using regional, instead of country-specific, names.…”

“…The search strategy will be informed by the African search filter, reported to have good sensitivity (74% for Medline and 73% for EMBASE), and improved precision from 1.3% to 9.4% in Medline and from 5% to 28% in EMBASE. 31 The African search filter comprises names of each country in Africa, and truncated terms to capture studies indexed using regional, instead of countryspecific, names. While the names of the countries in the filter are primarily in English, names in the relevant official language for each country (if different from the English version) were also included.…”