Psoriatic arthritis mortality & morbidities Save

Psoriatic arthritis (PsA) is a chronic condition with manifold clinical presentations. Health issues may be far beyond the classical associated conditions like uveitis, enthesitis etc.

The current study of Tillett et al (OP0231) assessed comorbidities and patient characteristics comparing psoriasis patients with or without PsA. BABDIR was the data source used for this analysis, which includes patients on ustekinumab or csDMARDs. He showed that the prevalence of depression, obesity, diabetes or hypertension was higher in the PsO/PsA patients than PsO alone. PsO/PsA patients were also more often unable to work or to work full-time. Thus, this study provided an overview in the differentiated burden and facets of this chronic condition.

Two large population register based studies from Sweden and Israel have addressed the issue of comorbidities and mortality and combined provided valid insights on how to assess mortality risk in people with PsA.  

Wallmann et al (OP0218) identified people with at least one diagnosis of PsA from the Swedish National Patient Register and matched them 1:5 based on sex, region and age of first PsA diagnosis. The observation period was between 2007 and 2018. Cases diagnosed before 2007 were compared with those diagnosed during the observation period. A HR for death of 1.11 attributed to 3121 deaths/268402 person-years in PsA vs. 12884 deaths/1302250 person-years. In sub-analyses a difference in mortality could only be seen in women and those diagnosed before 2007. In this population PsA had a higher comorbidity burden than the general population. (i.e CVD 41% vs 31%). There was no adjustment done for comorbidities to purely address the question on mortality of PsA patients including their typical associated features or conditions, summarised in 10% higher mortality risk as the general population (this 10% gap was seen after 10 years).

Haddad et al (OP0231) analysed data from the Clalit Health database, which includes half of Israel’s population for the observation period 2003 to 2019. 1 to 4 matching on sex, age, ethnicity and index date was done, resulting in 5275 PsA patients and 21 011 controls. 8.9% and 7.9% of PsA and controls respectively died during a mean follow-up of 7.2 years. The crude HR for mortality risk was 1.16, but only 1.02 (CI: 0.9-1.15) when adjusted for comorbidities, smoking, socioeconomic status and hospitalisation history. Risk factors for death in particular were lower socioeconomic status, obesity, age, male sex, prior hospitalisation and non-use of cDMARDs. 

People with PsA seem to have higher mortality risk, however this resembles the risk of the general population when adjusting for more detailed patient characteristics. In the Swedish study, interestingly, no differences in mortality in men were found, whereas men were at higher risk in the study from Israel. Exploring comparatively, the distribution of comorbidities seems to be similar in the two studies, however, comorbidities were listed in more detail in the study from Israel. The rate of bDMARD users in Israel seemed to be higher than in Sweden and vice versa for csDMARD users. Neither of the studies could identify clear differences in causes of death between PsA patients and the general population. 

It would be interesting to see the even further adjusted (particularly comorbidities) mortality risk for the Swedish population for better comparison of potentially geographical effects. It might be possible to speculate that comorbidities are drivers of mortality in PsA and since PsA patients seem to have higher comorbidity burden than the general population we need to account for this in clinical practice and choices of treatment.