Variation of Age in Clinically Overt Mitral Stenosis Patients from Two Different Countries: A Cross-National Study

  • Y. R. Limbu Shahid Gangalal National Heart Center, GPO Box 11360, Kathmandu
  • B. Dali Institute of Medicine, TUTH, Kathmandu
  • M. B. Khatry-Chhetry Shahid Gangalal National Heart Center, GPO Box 11360, Kathmandu
  • A. Maskey Shahid Gangalal National Heart Center, GPO Box 11360, Kathmandu
  • Huijun Zhu Shanghai Medical University, Shanghai
  • W. M. Pan Shanghai Medical University, Shanghai

Abstract

Rheumatic mitral stenosis (MS) remains common in developing countries and the disease advances morerapidly in underdeveloping areas. To compare the ages of clinically overt rheumatic MS patients from two different countries, retrospective data analysis was carried out from Institute of medicine, TUTH, Kathmandu,Nepal and Shanghai Medical University, Shanghai, PR China. The age of 63 patients (1 8M, 45F), involved from Nepal, ranged from 11 to 68 years and the age of 154 study subjects (53M, IOIF), involved from PR China,ranged from 10 to 79 years. Heart rhythm profile was recorded from the case history. Unpaired student's t-test was used to compare the ages of clinically overt MS patients from two countries and patients' ages were also compared according to the heart rhythm profile. The values of 50th and 95th percentile of age of study subjects from two different counties were separately calculated. P<0.05 was considered as the point of statistical significance. Clinically overt MS patients from Nepal were found significantly younger than their Chinese counter parts (34.5+15yr and 44.7+12yr, P<0.001). Fifty percent of Nepalese and Chinese study population were below 30.4yr and 43.8yr of age respectively and 95th percentile of Nepalese and Chinese study subjects were respectively 58.8 and 66.6 years of age. Patients in normal sinus rhythm (NSR) were found significantly younger than patients in atrial fibrillation (AF) in both countries (Nepal; 27.5+12.7yr and 40.7+14.4yr,P<0.001 and China; 36.3 + 10.3yr and 49.4+11yr, P<0.001). Nepalese NSR group was markedly younger than Chinese NSR group  (27.5+ 12.7yr and 36.3 + 10.3yr, P<0.01) and the age difference between AF groups from two countries also reached statistical significance (40.7+14.4yr and 49.4 +14.4yr, P< 0.01). Conclusions: Symptomatic Nepalese rheumatic MS patients are found significantly younger than Chinese MS patients. Earlier onset of AF among Nepalese MS patients can be found when compared with Chinese MS patients. The mean age of symptomatic rheumatic MS patients varies for country to country.