Psoriatic Arthritis – I Feel it in My Bones?

Psoriatic arthritis (PsA) is a disease that can be associated with both osteoproliferation and bony erosions. Because of the complexities of bone involvement in PsA, one may wonder if other disorders of bone, such as osteoporosis, are associated with PsA? Ali Aldei and colleagues from the University of Toronto (abstract #1702) presented a poster that analyzed bone mineral density (BMD) in patients with PsA, in addition to investigating the possible associations with measures of disease activity and functional capacity.

They analyzed 61 patients, mostly males, from their PsA clinic who underwent a BMD scan of the spine (L1-L4) and left femoral neck. The percentage of patients with T-scores equal to or less than -2.5 SD as well as a Z-score of 1.0 SD or less, were calculated. According to the WHO definition, spinal osteoporosis was found in 3% of patients and femoral neck osteoporosis in 5% of patients. Osteopenia of the spine was found in 28% of patients and femoral neck osteopenia was found in 39%.

Measures of disease activity in these patients, including tender joint count, swollen joint count, damaged joint count, patient global, physician global, presence of enthesitis, nail involvement, ESR, CRP, HAQ, and Psoriasis Area Severity Index (PASI score) were documented for the recruited patients at the time of BMD assessment. These disease activity measures, both clinical and laboratory in nature, were not found to be statistically associated with bone density. The prevalence of osteoporosis was not increased in these patients overall.

So although bone is a major player in PsA, osteoporosis does not seem to be associated, at least in this study, with PsA disease activity. Do you routinely screen your PsA patients for osteoporosis???

More reports from ACR 2015