PsA: psoriatic arthritis; r: Pearson coefficient; HDL: high-density lipoprotein; LDL: low-density lipoprotein; VLDL: very-low-density lipoprotein; IL-6: interleukin 6; BSA: body surface area (% of body areas affected by psoriatic lesions); PASI: psoriasis area severity index. The gene discussed is IL6; the disease is psoriatic arthritis.