Hsu YT, et al. - Authors assessed the effect of diabetes mellitus on clinical outcomes of non-surgical periodontal therapy. They conducted searches in electronic databases to screen studies published from January 1960 to August 2018. Based on the limitations of the study, no significant effect of diabetes mellitus (HbA1c ≥8.5%) was seen on short-term clinical periodontal outcomes of non-surgical periodontal treatment. Findings suggested a positive correlation between probing depth (PD) reduction and baseline PD difference, and a negative association between PD reduction and age.