Quality of methods and reporting in association studies of chronic periodontitis and IL1A−889 and IL1B+3953/4 SNPs: A systematic review

Abstract

Objective The aim of this systematic review was to evaluate the quality of reporting and methodology in genetic association studies between IL1A −889 and IL1B +3954 polymorphisms and chronic periodontitis. Background Evidence provided by periodontal research on genetic risk factors is of uttermost importance in clinical practice as a possible diagnostic and prognostic tool for periodontitis. Inadequate reporting of results as well as high risk of bias due to methodological inconsistency hampers the integration of evidence in terms of clinical applicability. Methods This review includes case‐control studies in humans published between 1997 and July 2017. Searching was conducted through MEDLINE, EMBASE, and search handing. Specific scoring systems have been developed to evaluate the quality of methods and reporting. Each article was scored according to its adequacy, and then, the total number and the percentage of items positively qualified for both methods and reporting were calculated. The quality of methods in studies scoring 0‐6, 7‐12, and 13‐16 was, respectively, considered poor, moderate, and good. For reporting, scores of 0‐9, 10‐18, and 19‐26 were deemed of poor, moderate, and good quality, respectively. Pearson's correlation coefficient was calculated to explore the correlation between the year of publication and the quality in terms of methods and reporting. Results From the 531 screened studies, 52 met the inclusion criteria and were thus included in the study. The quality of methods and reporting of published genetic association papers on IL1 and chronic periodontitis is moderate. On a scale from 0 to 16, the mean score for methods of the reviewed studies was 8.19 ± 1.93. The items more frequently considered inadequate concerned the handling of confounders in statistical analysis, especially oral hygiene habits, socioeconomic status, subgingival colonization of specific periodontal pathogens, and stress. A significant positive correlation was found between the year of publication and the quality scores in terms of method (r = 0.401, P = 0.003). In terms of reporting, the mean score was 14.83 ± 3.04 on a scale from 0 to 26 and it was considered overall moderate. No statistically significant correlation was found between the year of publication and the quality of reporting (P = 0.266). Conclusions The association between IL1A −889 and IL1B +3954 polymorphisms and chronic periodontitis is questionable due to methodological inconsistency. Evidence arising from meta‐analysis is unreliable due to high risk of bias and moderate quality in terms of reporting.

Evaluation of interleukin 10, interleukin 1-beta, and tumor necrosis factor-alpha gene polymorphisms in patients with periodontitis and healthy controls

“…We showed that carriers of the T allele of the IL-1ß + 3954 gene are at a higher risk for CP. Based on the latest meta-analysis on this subject by Citterio et al, the association between IL-1ß + 3954 C/T and CP has been questionable because of the methodological inconsistency of relevant studies [22]. For improvement of the methodological quality, Citterio et al [22] suggested multicentric studies with sufficiently powered samples, stricter criteria for the groups, and adjustment for confounders.…”

“…The relationship between several SNPs and periodontitis has been questionable and more clinical data are needed to draw a reliable conclusion in this regard [22,23]. Furthermore, it is proved that the association between gene polymorphisms and periodontitis differs based on race [24,25].…”