Randomized clinical trials in periodontology: focus on outcomes selection

Abstract

Randomized clinical trials (RCTs) are human studies carried out to compare different treatments or interventions, and their results are used to support clinical decision-making and improve patient care. Herein, the aim of this study was to review the selection process of study outcomes in periodontology. Primary outcomes should draw the main conclusions of the study, whereas secondary outcomes should only be used to help explain the main findings and generate future research hypothesis. Outcomes are classified as clinically relevant (CROs) or surrogate outcomes. CROs -the first option for primary outcome variables -should convey not only substantial health benefits, but also be deemed important by patients. In periodontology, tooth loss/retention and oral health-related quality of life (OHRQoL) are examples of CROs. While tooth loss has main limitations as a primary outcome, emerging evidence suggest that patient-reported outcome measures (PROMs) can accurately detect OHRQoL following periodontal therapy. When CROs cannot be assessed, validated surrogate outcomes can be used as proxies. Primary outcome variables should reflect a treatment endpoint at the patient level that can be easily used to inform decision-making in daily practice. These outcomes should allow the implementation of a treat-to-target concept in which the intervention can be clearly judged against a prespecified treatment target. Recently, the presence of at most 4 sites with periodontal probing depth ≥5 mm post-treatment was suggested as an effective endpoint for periodontal trials. In perspective, a combination of validated clinical parameters and PROMs will provide a more comprehensive assessment of periodontal treatments.

Effect of supragingival plaque control on recurrent periodontitis and clinical stability among individuals under periodontal maintenance therapy: 10‐year follow‐up

“…We did not evaluate PROM in this present study, but combining outcomes that assess oral health‐related quality of life and clinical parameters to define the endpoint for periodontal treatment could provide a more comprehensive assessment of new treatments and interventions 48 . A previous study conducted by our group 49 in this same cohort aimed to assess the effects of compliance during 6 years of PMT on the oral impact on daily performance (OIDP) measures and showed that regular compliers had lower OIDP scores when compared to irregular ones.…”

Selective outcome reporting bias is highly prevalent in randomized clinical trials of nonsurgical periodontal therapy

“…Nonsurgical periodontal therapy (NSPT) has been extensively studied for decades. Several therapies and adjuncts have been tested, and many outcomes have been used to measure the efficacy of these interventions 20 . However, it is necessary to investigate discrepancies between registered protocols and their respective publications regarding these outcomes.…”

“…Several therapies and adjuncts have been tested, and many outcomes have been used to measure the efficacy of these interventions. 20 However, it is necessary to investigate discrepancies between registered protocols and their respective publications regarding these outcomes. Therefore, this study aimed to assess the prevalence of SOR in clinical trials of NSPT, comparing protocols and publications, in addition to verifying the factors that may be associated with SOR.…”