Is pain associated with premature mortality in patients with psoriatic arthritis? A nested case-control study using the DANBIO Register

OBJECTIVES: It has been hypothesized that the presence of chronic pain causes excess mortality. Since chronic pain is prevalent among patients with PsA this potential association should be explored. We aimed to investigate whether higher cumulative pain intensity is associated with an excess mortality risk in patients with PsA.

METHODS: A nested case-control study using data from the nationwide DANBIO Register (Danish Database for Biological Therapies in Rheumatology) Register and Danish healthcare registers. Cases were patients who died and corresponding to the date of death, matched on sex, year of birth and calendar period at the time of death with up to five controls. Exposure of interest was mean pain intensity reported during the time followed in routine rheumatology practice. Pain intensity was measured using a visual analogue scale from 0 to 100 and conditional logistic regression was used to calculate odds of mortality per 5 unit increase in pain while adjusting for confounders.

RESULTS: The cohort consisted of 8019 patients. A total of 276 cases were identified and matched with 1187 controls. Higher mean pain intensity was associated with increased odds of mortality [odds ratio 1.06 (95% CI 1.02, 1.10)] in the crude model, but there was no association [odds ratio 0.99 (95% CI 0.95, 1.03)] when adjusting for additional confounders. Factors shown to increase the odds of mortality were recent glucocorticoid use, concomitant chronic obstructive pulmonary disease, diabetes mellitus, cancer and cardiovascular disease.

CONCLUSION: These results indicate that experienced pain in itself is not associated with premature mortality in patients with PsA. However, recent glucocorticoid use and concurrent comorbidities were.