Rheumatoid arthritis (RA) is associated with chronic periodontitis (CP) due to shared risk factors, immuno‐genetics and tissue destruction pathways. Human cathelicidin LL‐37 has been suggested as a possible mechanistic link for these diseases. This study investigated the levels of salivary and serum LL‐37 in subjects with RA and CP and their correlation with disease parameters.

Subjects were allocated into RA (n = 49) or non‐RA (NRA) (n = 55) groups, where 3 subgroups were further established; chronic periodontitis (CP), gingivitis (G) and periodontal health (H). Demographic and periodontal parameters were collected. Rheumatology data were obtained from hospital records. Serum and salivary LL‐37 levels were measured using enzyme‐linked immunosorbent assay and compared for all groups.

For salivary LL‐37, RA‐CP was significantly higher than NRA‐G and NRA‐H (P = .047). For serum LL‐37, all RA and NRA‐CP were significantly higher than NRA‐G and NRA‐H (P = .024). Salivary LL‐37 correlated negatively with clinical attachment loss (CAL) (P = .048), but positively with erythrocyte sedimentation rate (ESR) in RA‐H (P = .045). Serum LL‐37 showed positive correlation with ESR (P = .037) in RA‐G, with C‐reactive protein (P = .017) in RA‐H, but negative correlation with number of teeth (P = .002) in NRA‐CP. Rheumatology data correlated positively with periodontal parameters in RA‐CP group.

NRA‐CP subjects with high serum LL‐37 should receive comprehensive periodontal therapy. Positive correlation between rheumatology data and periodontal parameters showed that RA disease stability may be obtained by assessing the periodontal condition. Periodontal therapy is necessary to compliment RA treatment to achieve optimum outcome for RA patients with concurrent CP.