Vitamin D Status in Rheumatoid Arthritis Patients
Vitamin D Status in Rheumatoid Arthritis Patients
Ninety-seven consecutive RA patients without vitamin D supplementation (86 women and 11 men aged 59.4 ± 12 years, with the mean disease duration 8.1 ± 9 years [0.1–40 years]) hospitalized in the Department of Rheumatology WIM CSK MON were included in the study. The control group consisted of 28 osteoarthritis (OA) patients (25 women and 3 men aged 56.2 ± 15 years). Seventy-six patients were hospitalized because of RA exacerbation or the need of treatment modification; the other 21 patients were newly diagnosed with RA during hospitalization. The patients signed the informed consent form. The study was approved by the local ethical committee. In 27 patients, testing was performed before RA treatment or during the first weeks of treatment. The data concerning disease duration, previous treatment, comorbidities, body mass index (BMI), the frequency of being outdoors, and the level of PA have been collected. Patients with RA completed the questionnaires: SF-36, Beck Depression Inventory (BDI), and HAQ, and determined the severity of pain and fatigue on visual analog scale (VAS). To calculate the grades of the SF-36 scale, we used the rules established for the Polish version of the scale by Tylka and Piotrowicz. The results were converted to percentages assuming that 100% means maximum welfare in a given subscale. Physical activity was quantified in a 5-grade scale from 0 (no exercises) to 4 (exercises at least 3 times a week for a minimum 1 hour). Disease activity was assessed according to the Disease Activity Score in 28 Joints (DAS28). Components of DAS28 are erythrocyte sedimentation rate, patient's global assessment (0–100), and swollen and tender joint count (both 0–28). High disease activity was defined as DAS > 5.1, moderate as 3.2 < DAS28 ≤ 5.1, low as 2.6 ≤ DAS28 ≤ 3.2, and remission as DAS28 < 2.6. The degree of joint damage was determined according to Steinbrocker's scale. Laboratory tests included complete blood count, serum concentration of creatinine, transaminases, calcium (Ca), phosphates (P), parathyroid hormone (PTH), and 25-hydroxycholecalciferol (25(OH)D). For the measurement of 25(OH)D, we used automated immunoassay DiaSorin Liason (Piaseczno, Poland). Serum 25(OH)D concentration of less than 20 ng/dL was defined as vitamin D deficiency.
In the statistical analysis, we used Statistica version 10.0 (StatSoft, Kraków, Poland). Results are reported as mean (SD) for continuous variables and n (%) for categorical variables. Student t test, Mann-Whitney U, and 1-way analysis of variance were used for the comparison of independent variables. Multiple regression analysis was used to assess relative importance of independent variables. Pearson or Spearman correlation was used for determining correlation. P < 0.05 was considered statistically significant.
Materials and Methods
Ninety-seven consecutive RA patients without vitamin D supplementation (86 women and 11 men aged 59.4 ± 12 years, with the mean disease duration 8.1 ± 9 years [0.1–40 years]) hospitalized in the Department of Rheumatology WIM CSK MON were included in the study. The control group consisted of 28 osteoarthritis (OA) patients (25 women and 3 men aged 56.2 ± 15 years). Seventy-six patients were hospitalized because of RA exacerbation or the need of treatment modification; the other 21 patients were newly diagnosed with RA during hospitalization. The patients signed the informed consent form. The study was approved by the local ethical committee. In 27 patients, testing was performed before RA treatment or during the first weeks of treatment. The data concerning disease duration, previous treatment, comorbidities, body mass index (BMI), the frequency of being outdoors, and the level of PA have been collected. Patients with RA completed the questionnaires: SF-36, Beck Depression Inventory (BDI), and HAQ, and determined the severity of pain and fatigue on visual analog scale (VAS). To calculate the grades of the SF-36 scale, we used the rules established for the Polish version of the scale by Tylka and Piotrowicz. The results were converted to percentages assuming that 100% means maximum welfare in a given subscale. Physical activity was quantified in a 5-grade scale from 0 (no exercises) to 4 (exercises at least 3 times a week for a minimum 1 hour). Disease activity was assessed according to the Disease Activity Score in 28 Joints (DAS28). Components of DAS28 are erythrocyte sedimentation rate, patient's global assessment (0–100), and swollen and tender joint count (both 0–28). High disease activity was defined as DAS > 5.1, moderate as 3.2 < DAS28 ≤ 5.1, low as 2.6 ≤ DAS28 ≤ 3.2, and remission as DAS28 < 2.6. The degree of joint damage was determined according to Steinbrocker's scale. Laboratory tests included complete blood count, serum concentration of creatinine, transaminases, calcium (Ca), phosphates (P), parathyroid hormone (PTH), and 25-hydroxycholecalciferol (25(OH)D). For the measurement of 25(OH)D, we used automated immunoassay DiaSorin Liason (Piaseczno, Poland). Serum 25(OH)D concentration of less than 20 ng/dL was defined as vitamin D deficiency.
In the statistical analysis, we used Statistica version 10.0 (StatSoft, Kraków, Poland). Results are reported as mean (SD) for continuous variables and n (%) for categorical variables. Student t test, Mann-Whitney U, and 1-way analysis of variance were used for the comparison of independent variables. Multiple regression analysis was used to assess relative importance of independent variables. Pearson or Spearman correlation was used for determining correlation. P < 0.05 was considered statistically significant.