Reachout Orthopedics - Issue 1

presence of hypertension (yes vs. no); and use of analgesic drugs (yes vs. no). Data of Cox’s regression analysis were reported as hazard ratios (HRs) with correspondent 95% confidence intervals (CIs). In secondary analyses, specific joints affected by OA (categorized as knee, hip, hand, back/neck, or other joints) and the presence of knee OA, defined through radiological and clinical criteria, were taken as exposure variables. Participants without any presence of OA were taken as reference also in these analyses. To test the robustness of our analyses, sensitivity analyseswere conducted evaluating the interaction between the presence of self- reported and radiological/clinical diagnosis of OA and selected factor (e.g. gender, race, education, smoking habits, yearly income and presence/absence of diseases at baseline) in predicting CVD at follow-up. Gender emerged as potential moderator of our analyses (p for interaction <0.001). Thus the data are presented also by gender. All analyses were performed using the SPSS 21.0 for Windows (SPSS Inc., Chicago, Illinois). All statistical tests were two-tailed and statistical significance was assumed for a p-value <0.05. Results Study Participants At baseline, among 4,796 potentially eligible individuals, we excluded 313 had already a CVD, 21 did not have any information regarding OA and 197 without data during followup evaluations, obtaining a final sample of 4,265 participants. Baseline Analyses Overall, 4,265 participants (1,740 males; 2,525 females) with a mean age of 60.8±9.1 (range: 45-79) years were eligible for inclusion in the current study. At baseline, 1,775 people with OA (41.6%) were compared with 2,490 participants without OA. The baseline characteristics of the OA and non-OA participants are summarized in the Table 1 in the sample as whole and divided by gender. Independently from gender, participants with OA were significantly older and used more frequently analgesic drugs than those without OA. In men, participants with OA were more frequently obese, smokers, diabetic than those without OA, whilst in women, participants with OA were more frequently whites, sedentary (as shown by lower PASE scores), more educated and with a higher presence of co-morbidities as shown by higher Charlson's score (Table 1). Association Between Baseline Osteoarthritis and Incident Cardiovascular Disease After a mean period of 8.2 years, 416 individuals (9.8% of baseline population) (113 developed heart attack, 190 heart failure, 151 strokes or other cerebrovascular conditions, and 72 peripheral artery disease) developed a CVD event. The global incidence rate of CVD was 16 (95% CI: 0-41) events for 1000 persons-year. As shown in Figure 1, the incidence of CVD was significantly higher in those having OA at baseline compared to those without (OA: 17; 95% CI: 0-48 vs. no OA: 14; 95% CI: 0-37/1000 events for 1000 persons-year; p<0.001). Table 2 shows the Cox’s regression analyses by OA presence and for OA specific site. Taking those without any presence of OA as reference and after adjusting for 11 potential baseline confounders, OA was associated with a significant higher risk of CVD (HR=1.27; 95% CI: 1.03-1.56, p=0.02), particularly when OA affected hand (HR=1.31; 95% CI: 1.01-1.68, p=0.04). The association between any site OA and incident CVD remains significant in women (HR=1.50; 95% CI: 1.13-2.00, p=0.005), but not in men (Table 2). In women, OA affecting hip (HR=1.51; 95% CI: 1.00-2.27, p=0.048) and hand (HR=1.65; 95% CI: 1.21- 2.24, p=0.001) increased the risk of CVD, whilst in men no site was at increased risk of developing CVD. Knee OA defined through radiological and clinical presence, did not show any significant association with incident CVD in the sample as whole (HR=0.94; 95% CI: 0.76- 1.15, p=0.52), nor in men (HR=1.03; 95%CI: 0.76-1.34, p=0.85) or in women (HR=0.85; 95% CI: 0.64-1.14, p=0.28). Table 1: Baseline characteristics classified according to presence or not of osteoarthritis (OA). Whole sample Men Women Variable OA (n = 1,775) No OA (n = 2,490) OA ( n= 626) OA (n = 1,149) No OA (n = 1,376) Age (years) 62.3 (8.6) 59.8 (9.1)*** 61.7 (9.2) 59.6 (9.4)*** 62.6 (8.6) 60.0 (8.9)*** White race (n, %) 1501 (84.6) 1937 (77.9)*** 541 (86.6) 937 (84.2) 960 (83.6) 1000 (72.7)*** BMI (Kg/m 2 ) 28.7 (4.8) 28.4 (4.8)** 29.1 (4.1) 28.6 (4.1)* 28.6 (5.2) 28.2 (5.2) PASE (points) 157.5 (81.4) 167.1 (83.0)*** 176.8 (88.3) 181.2 (88.5) 147.0 (75.5) 155.7 (76.4)** Smoking (previous/current) 853 (48.6) 1099 (44.8)* 335 (54.3) 500 (45.5)** 518 (45.5) 599 (44.2) Degree (n, %) 586 (33.3) 731 (29.6)** 245 (39.6) 400 (36.3) 341 (29.8) 331 (24.3)** Yearly income (< $50,000) 654 (36.8) 846 (34.0) 161 (25.7) 279 (25.0) 493 (42.9) 567 (41.2) Medical conditions Diabetes (n, %) 125 (7.2) 162 (6.7) 56 (9.1) 70 (6.5)* 69 (6.1) 92 (6.9) Cancer (n, %) 87 (4.9) 114 (4.6) 41 (6.5) 64 (5.8) 46 (4.0) 50 (3.6) Hypertension (n, %) 359 (20.2) 217 (20.8) 144 (23.0) 262 (23.5) 215 (18.7) 255 (18.5) Charlson comorbidity score 0.32 (0.71) 0.26 (0.71)*** 0.32 (0.76) 0.26 (0.76) 0.33 (0.68) 0.26 (0.66)*** Use of analgesic drugs (n, %) 930 (52.5) 735 (29.7)*** 293 (47.0) 305 (27.6)*** 637 (55.5) 430 (31.4)*** Notes: P-value: ***: p < 0.001; **: p < 0.01; *. p < 0.05; Numbers are mean values (and standard deviations) or number (and percentages), as appropriate; Unless otherwise specified, p values are calculated with an independent Student T-test for continuous and with a chi-square test for categorical variables, respectively; Abbreviations: BMI: body mass index; PASE: physical activity scale for the elderly 25 reachOut Orthopedics