We updated searches for a total of eight recommendations using five different approaches. Four of the recommendations were taken from the Colombian CPGs (9) and four from ADA guidelines (10). As shown in the supplementary appendix A, five of the recommendations were about treatment, two about diagnosis of complications and one about follow-up. Most recommendations were of moderate to high certainty of evidence, but the recommendation about follow-up had the lowest certainty of evidence (E level in the ADA guideline).
All five approaches required a similar number of steps (see supplementary Appendix B), from entering the search terms or designing the search strategy to download and export the selected references. Although two of the approaches exhibit some characteristics such as lack of time filter or manual selection of references, which can make the search process less efficient. For approach C, since it was not necessary to design and run searches, but simply find the L.OVE based on the PICO question, it required less effort. Although approach E had a search feature based on the PICO question, it did not allow the exporting of files and therefore all the strategies had to be performed using the advanced features.
Retrieval process across search approaches for the eight recommendations of interest (Fig. 1).
Despite using the same terms and keywords in the searches, the approaches greatly varied in the number of articles retrieved. While approaches A, B and E yielded a similar number of references (407, 473 and 444 respectively), approach C (Epistemonikos, advanced) returned the lowest number (n = 318) of references and approach D (L.OVE) the highest (n = 505). As expected, most (78.7–90.1%) references were judged as definitely not eligible in the first round, but a range of 8.9–18.2% were left for further reclassification. After the selection performed by the three reviewers in the two rounds the total number of relevant references identified ranged from 20 to 31 (5.6 to 9.4% of all retrieved). Out of 136 references considered eligible at the end of the process (some of them repeated in two or more recommendations), two-thirds (91) were added in the second round of discussion among reviewers.
Diagnostic performance of the search approaches (Fig. 2).
Approach A (Pubmed) showed the highest sensitivity (50% with the others ranging from 24–33%) and the second-best specificity (93%, with the others ranging from 87–94%). Pubmed outperformed the other four search approaches in terms of its positive Likelihood ratio (6.73 compared with 2.23–4.19 of the other approaches), negative likelihood ratio (not shown in the Fig. 0.54, compared with 0.77–0.85 of the others) and, as a result, its diagnostic odds ratio (12.5 and 2.6–5.3, respectively).
Distribution of the references found eligible by the reviewers.
Table 1 shows the references retrieved by our five search approaches by recommendation and in total. The approaches retrieved 20–31 references for the 8 recommendations, but recommendation 1 accounted for 39% of all eligible references. Although Pubmed showed better “diagnostic performance” among the approaches, the approach with higher retrieval was (D) L.OVE, with 31 of 82 documents of interest (71 single references, as some documents were eligible for more than one recommendation). No search approach returned at least one reference for each of the 8 recommendations of interest. Individually, the approaches contributed with a relatively small portion (from 24–37%) of the eligible references. Likewise, the proportion of references provided solely each approach was relatively large (5–12 of the eligible references, that is 25–39% of their individual contribution).
Figure 3 shows the accumulative contribution of the eligible references (adding the 8 recommendations) provided by the 5 approaches, when the search sequence started by one or the other. It is noticeable that in none of the search sequences the eligible references reached an (arbitrarily, minimal) 80% threshold (n = 66), even when combining any 3 approaches. The relative contribution of (A) Pubmed seemed the higher among all approaches. As a result, to reach a goal of retrieving at least 80% of the eligible references, four search approaches should be added, only when Pubmed was included in the search.
Figure 4 shows the accumulative contribution of the searches for all recommendations, when starting with Pubmed. Despite the variation of the yield for the recommendations, there is consistency in the need to add search approaches to reach a substantial number of the eligible references. Although Pubmed identified roughly half of the references for most recommendations, only in one of the eight situations (EBR7) was sufficient as search approach. Moreover, in two recommendations (EBR 5 and 8) Pubmed did not return references of interest.
Agreement between search approaches ( Table 2 )
This table shows the number of eligible references (n = 71) in agreement as found/not found (positive/negative), the proportion of observed/expected (by chance) agreement and the Kappa statistics for the ten possible pairs of search approaches. In 9 of the cases, the agreement statistics did not surpass that found by chance.