We hypothesized that patients with Legg-Calvé-Perthes disease (LCPD) might have higher risks of cardiovascular and blood diseases.
A total of 2579 patients with LCPD diagnosed between 1965 and 2005 were identified with the Swedish Inpatient Register. A total of 13 748 individuals without LCPD were selected randomly from among the Swedish general population, with matching according to year of birth, age, gender, and region of residence. Cox proportional-hazard regression analyses, with adjustment for socioeconomic index, were used to estimate relative risks. The patients also were compared with their same-gender siblings.
Patients with LCPD had a hazard ratio (HR) of 1.70 (95% confidence interval [CI]: 1.48–1.95) for cardiovascular diseases, compared with individuals without LCPD. There were statistically significantly higher risks for hypertensive disease, ischemic heart diseases, cerebrovascular diseases, and diseases of arteries, veins, and lymphatic vessels. There were statistically significantly higher risks for blood diseases, including anemias and coagulation defects (HR: 1.94 [95% CI: 1.51–2.49]), which were more pronounced among subjects >30 years of age at the follow-up (HR: 2.45 [95% CI: 1.77–3.41]). Patients also had statistically significantly higher risks of nutritional anemia (HR: 2.32 [95% CI: 1.41–3.81]) and hemolytic anemia (HR: 2.59 [95% CI: 1.72–3.92]). Analyses using siblings as the comparison group showed consistent results for cardiovascular diseases.
The results are consistent with the hypothesis that an insufficient blood supply to the femoral head, attributable to vascular pathologic conditions, is involved in the pathogenesis of LCPD.