Both psoriasis and hyperuricemia increase the risk for low trabecular volumetric bone mineral density (BMD) and impaired bone microstructure, according to study results published in Osteoporosis International.
To examine whether hyperuricemia among patients with or without psoriasis was associated with changes in volumetric BMD and bone microstructure, investigators conducted a case-controlled, 2-center study to establish and compare volumetric BMD and microstructure across patient populations.
A total of 130 participants were included in the study, with 44 (34% women) with normal levels of uric acid, 50 with hyperuricemia, 16 with psoriasis and hyperuricemia, and 20 with psoriasis and normal levels of uric acid. Body mass index (BMI) was higher among patients in the hyperuricemia group vs those in the normal uric acid levels group (P =.002), while smoking and alcohol intake was highest in the psoriasis group with normal uric acid levels (P <.001 and P =.002, respectively).
Investigators compared volumetric BMD and microstructural parameters in the hyperuricemia, psoriasis with hyperuricemia, and psoriasis with normal uric acid groups with the reference group. Significantly higher values for cortical volumetric BMD and cortical thickness were noted when comparing the reference group with the hyperuricemia group. After adjusting these bone parameters for age, sex, BMI, and diabetes, significant differences were found between the reference and hyperuricemia groups. A regression model identified significant differences in both average and trabecular volumetric BMD and trabecular number between the psoriasis with hyperuricemia and reference groups.
Serum markers were compared in a similar manner as bone parameters; investigators noted that uric acid was significantly higher in both groups with hyperuricemia compared with the reference group (P <.001). Creatinine levels were also higher in the hyperuricemia group but lower in the psoriasis with normal uric acid group compared with the reference group (P =.001 and P =.038, respectively). C-reactive protein levels were in the normal range but highest for the hyperuricemia group (P <.001); low levels of vitamin D were found in the psoriasis and hyperuricemia group, although these numbers did not reach statistical significance (P =.051). Bone turnover markers, including cross-linked C-telopeptide, intact N-terminal type 1 procollagen propeptide, Dickkopf-1, and sclerostin, were comparable between subgroups.
Results of a regression model based on demographic data identified that only women were associated with low trabecular volumetric BMD. Uric acid, BMI, and age did not show significant effects on either volumetric BMD or bone microstructure, but there was a significant relationship between diabetes and trabecular number. Across both hyperuricemia groups, the researchers found significant associations between vitamin D, sclerostin, intact N-terminal type 1 procollagen propeptide, and trabecular volumetric BMD.
Study limitations included the small number of cases in each subgroup and lack of information on prevalent fracture risk for patients.
“Hyperuricemia in combination with skin psoriasis is a risk factor for low trabecular volumetric [BMD] and impaired bone microstructure — even in the absence of gouty or psoriatic arthritis,” the researchers concluded.
Simon D, Haschka J, Muschitz C, et al. Bone microstructure and volumetric bone mineral density in patients with hyperuricemia with and without psoriasis [published online January 10, 2020]. Osteoporosis Int. doi:10.1007/s00198-019-05160