| Background and ObjectiveRheumatoid arthritis (RA) is a chronic inflammatory disease involving in many organs and tissues which is easily misdiagnosed at early, and causes to loss of joint and muscle function at later period. Predicted lifetime of RA patients shall reduce to3-10years. It is estimated by a study in Britain that the annually average cost of each patient in Britain is GBP50,000-80,000. The medical expense in China each year continues to rise. The DMARD used in clinical application for three years in Chengdu amounts to RMB29,0739million with annual average growth rate for11.6%. In addition, rheumatism professional starts late in China and many non-professional doctors lack adequate understanding about it which causes that it is very difficult to diagnose at early so as to bungle illness. Therefore, RA screening and prevention are not merely the common concern of international rheumatism scholars, but also a global public health event.Various countries in the world are positively conducting epidemiologic study of RA, such as British Norfolk, French EPIRHUM-2, RA Study Centre of University of Memphis in Tennessee of USA, NIH, CPR and North American SONORA. Morbidity study is conducted mainly in USA and European countries such as Britain while most of Asian countries except for Japan conduct the prevalence rate study. Global prevalence is1%about and average annual morbidity is0.02-0.05%. The study in North America and Northern Europe indicate that prevalence rate and morbidity of diseases go down after1960s. Few epidemiologic study of RA is made by developing countries due to different reasons. In that event, World Health Organization cooperated with ILAR to prepare WHO/ILAR COPCORD in1981. COPCORD project is to take into probably hazardous factors of disease account to prevent the wide development of rheumatism and to reduce the lack phenomenon of epidemiologic data related to rheumatism, especially in rural community of developing countries. The countries have conducted COPCORD study at present including:Philippines, Indonesia, Australia, Thailand, China, Pakistan, India, Vietnam, Bengal, Kuwait and Iran and etc.China first domestic epidemiological survey of rheumatism was started in1984. The RA morbidity is0.2%-0.37%in Mainland China and there is not significant difference of RA morbidity between north and south mainland or any notable discrepancy of race. The epidemiologic study of rheumatism has been performed in many places of China, but most of them do not have uniform or systematic method. There may be potential bias in the methodology and other factors may also affect the survey result.The aforesaid study is generally based on ACR standard of1987in the diagnosis, but it is impossible to differentiate early RA and early arthritis. Hence, the American College of Rheumatism and European League Against Rheumatism (ACR/EULAR) raised the classification criteria of rheumatoid arthritis in2010and focused on the early characteristics of disease. The clinical synovitis is a new standard center, including number of joints suffered from arthritis, abnormal rise of serum and duration of symptom in acute phase. In view of strict development standard of the latest ACR/EULAR methodology in2010, it is recommended that any survey on RA morbidity or prevalence rate based on the population be implemented as per the standard of epidemiology. RA is a multifactorial disease caused by interaction of genetic and environmental factors. The main hazardous factors of this disease include genetic predisposition, gender, age, smoking and socioeconomic status. Generally speaking, most of these factors are related to the occurrence and severity of disease. The protective factors include drinking, pregnancy, oral contraceptive, fish, olive oil and vegetables. At present, the survey on large epidemiologic study sample is in shortage and relatively few hazardous factors of domestic RA patient are known in China. China is features with vast territory and variable terrain and RA epidemiology is also different in different places, which the survey on RA epidemiology in Central China never reflects, therefore, COPCORD study is performed in Luohe in the south of Henan Province and the latest ACR/EULAR diagnosis criteria in2010is used for statistical survey to reveal RA prevalence rate and awareness rate of adults, analyze hazardous factors and offer basis for formulating reasonable control strategy.Methods1. Objective of survey The permanent residents of45years old or above from the sampling areas in four communities of Luohe urban area, four communities and eight villages of two county-level cities subject to Luohe were selected as the objects of study during July2011～December2011. The sample size shall cover8,610people. The participants shall accept questionnaire survey on general situation and medical history, physical examination and laboratory examination.2. Study methods The study is constituted by two phases. Phase I:sample survey phase in which all permanent residents of45years old or above from the sampling areas accept questionnaire survey. According to sample survey result, the object of study with joint score=1and time>6weeks or joint score>1can enter Phase II, namely, laboratory examination phase in which the blood is drawn to test serology and acute phase reactant.3. Questionnaire survey The specialists, postgraduates and interns in the Department of Rheumatology and Clinical Immunology, who have accepted specialized training, serve as questionnaire surveyors to focus on the centralized survey that is completed by household survey. The questionnaire content includes general demographic data, behavior habits, RA and hazardous factor screening and family history. See the attached table.4. Quality control The repeated survey is implemented according to5%sample size, then the representation and reliability of samples are tested as per the repeated survey data and the blood biochemical test shall be in line with laboratory quality control standard.5. Diagnosis criteria RA diagnosis shall be based on RA diagnosis criteria issued by ACR/EULAR in2009/2010. It is defined that the diagnosis comprises the following four parts. When total score of four parts is more than6points, RA can be confirmed in the diagnosis.6. Statistical methods ALL field epidemiological survey data and relevant laboratory examination data shall be input into the computer by the special person with EpiData3.0software. After the data processing, statistical analysis shall be implemented by SPSS13.0software so as to form the standardized prevalence rate according to age and gender from the sixth population census of Luohe City. x±s indicates measurement data and the comparison among groups shall be based on t inspection, analysis of variance and rank sum test; the comparison of numeration data shall be based on x2inspection and trend test. The factors related to RA shall be analyzed in the logistic regression analysis of multiple factors. The inspection level is a=0.05.Results1. The survey totally covers8,610residents among whom8,274people are effective samples, with response rate of96.10%, about45-91years old and their average age of61.36±7.39years old. With regard to the distribution of age group, the patients of60～65years old account for the most part, about27.50%(2,275people). Regarding gender distribution, there are3,361males (40.62%) whose average age is62.78±7.59years old and4,913females (59.38%) whose average age is60.38±7.09years old, with male/female ratio of1:1.46.2. Basic information on all parts in RA diagnosis definition 2.1The knee joint and shoulder joint are the most affected large joints. The affected rate on the left side and right side of knee joint is respectively5.63%and5.66%so that total affected ratio is11.29%. The affected rate of shoulder joint is7.88%, with3.87%and4.01%respectively on the left side and right side. The interphalangeal joints are major affected small joints, with affected rate around2.01%. The prevalence rate with the respective score of0,1,2,3and5points corresponds to13.62%,7.57%,2.79%,1.87%and0.23%. Overall arthralgia prevalence rate of the male is clearly higher than that of the female (x2=18.075P<0.0001), large joints are mainly affected while the prevalence rate of small joints which are affected is lower than that of the female,(3.11%VS2.32%,x2=4.630P=0.031). As regards gender distribution, the affected joints with the score of2,3and5points always get high during60-64years old where the affected rate of the joint is respectively2.90%,2.02%and0.26%.2.2Duration of affected joints The percentage of the joint with score of0,1,2,3,5points and duration>6weeks is12.75%,6.79%,2.45%,1.76%and0.21%, respectively.2.3Serological test The serology RF and anti-CCP antibody titer are in skewed distribution. The low titer positive rate and high titer positive rate of RF and anti-CCP antibody are respectively6.62%,1.96%and5.48%,1.55%. Therein, low titer positive rate and high titer positive rate of RF and anti-CCP antibody of the male are respectively4.19%and1.05%;0.72%and4.76%, clearly lower than that of the female. As for the object of study with joint score of3points and5points, low titer positive rate and high titer positive rate of RF and anti-CCP antibody are obviously higher than that of the object with joint score of1point (P<0.05).2.4Test of acute phase reactant The rising prevalence rate of ESR and CRP is17.48%and14.27%respectively, with rise rate of19.75%. The comparison between different genders shows that ESR rise rate of the female is obviously higher than that of the male (22.22%VS10.21%,x2=23.123P=0.0001), that CRP rise rate is also in the same trend for different genders (16.58%VS10.73%, x2=6.460P=0.011) and that the prevalence rate of acute phase reactant will be rise with the increase of joint score, with trend test (x2=152.675P<0.0001).3. Prevalence of RA The rough prevalence of RA in middle-aged and elderly population of Luohe City is0.76%. The prevalence rate is0.71%after standardization according to the age and gender distribution from the sixth national population census. In the age distribution, the prevalence rate of patients who belong to65～69years old and60～64years old is relatively high, respectively1.13%and0.84%while1.10%and0.77%based upon standardization; in terms of comparison between different genders, the prevalence rate of female patient is higher than that of male patient (1.02%VS0.39%,x2=10.513P=0.001).4. RA risk factors The result indicates that the gender (female), residential floor (the1st floor), smoking and genetic factors are key risk factors for RA.5. Awareness, cognition and treatment of RA47people among definite63objects of RA survey are aware that they suffer from RA so that the awareness rate is74.60%, but there are only29objects of the study who have correct cognition of RA so that the cognition rate is46.03%. The treatment is not optimistic either. Most patients concentrate on local small hospitals or private clinics, with the treatment rate of71.43%and control rate of18.57%.Conclusions1. The epidemiological survey in Luohe region is firstly issued according to2009/2010ACR/EULAR.2. The prevalence rate of RA is0.71%, with1.02%of the female and0.39%of the male.3. RA morbidity is related to the gender and living environment4. The awareness rate and treatment rate of RA are relatively low in Luohe region. |
PDF Full Text Request