Presence of arthritis does not affect osteoporosis in psoriasis patients
MedWire News: Psoriasis patients are at increased risk for osteoporosis, based on serum osteoprotegrin (OPG) elevations, regardless of whether they have psoriatic arthritis (PsA), say Egyptian researchers.
However, the results of dual energy X-ray absorptiometry (DEXA) revealed that osteoporosis is more significant - particularly in the femoral neck and wrist - in psoriasis patients with PsA compared with those without.
"Because proinflammatory cytokines are increased in psoriasis, patients with this disease may be more prone to osteoporosis than healthy individuals," write Enas Attia (Ain Shams University, Cairo) and colleagues in the International Journal of Dermatology.
The group assessed the presence and severity of osteoporosis in 34 patients with psoriasis (group I), and 16 with psoriasis and PsA (group II), using DEXA and OPG measures. Twenty healthy volunteers acted as age- and gender-matched controls.
A total of 17.6%, 5.9%, and 17.6% of group I patients had osteoporosis, defined as a T score (standard deviations [SDs] from mean for healthy young adult) below -2.5 at the lumbar spine, neck of femur, and wrist, respectively. The corresponding values in group II were 12.5%, 37.5%, and 68.8%.
DEXA results - indicating osteoporosis severity - showed significantly lower T and Z (difference in SD of DEXA from controls) scores at the lumbar spine, femoral neck, and wrist in both groups I and II, versus controls.
Furthermore, group II had significantly lower mean T and Z scores at the femoral neck and wrist compared with group I, at -1.08 versus -0.35 and -1.03 versus -0.36 (femur neck), and -1.87 versus -1.17 and -2.03 versus -1.14 (wrist), respectively.
Serum OPG levels ranged from 8 to 35 pg/ml in group I and from 14 to 35 pg/ml in group II, compared with 3 to 15 pg/ml in the control group. This represented a highly significant elevation in groups I and II compared with controls, note Attia et al.
In contrast, there was no significant difference in OPG levels between psoriasis patients and PsA patients.
Finally, the researchers observed that the extent of skin involvement and Psoriasis Area Severity Index scores were greater in PsA patients than in psoriasis patients without arthritis.
"Therefore, in psoriatic patients with extensive skin involvement and/or nail involvement, screening for joint involvement should be performed," conclude Attia and co-workers.
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By Sarah Guy