Prevention of disease complications through diagnostic models: how to tackle the problem of missing data?

Diagnostic models are frequently used to assess the role of risk factors on disease complications, and therefore to avoid them. Missing data is an issue that challenges the model making. The aim of this study was to develop a diagnostic model to predict death in HIV/ AIDS patients when missing data exist. HIV patients [n=1460] referred to Voluntary Consoling and Testing Center [VCT] of Shiraz southern Iran during 2004-2009 were recruited. Univariate association between variables and death was assessed. Only variables which had univariate P< 0.25 were selected to be offered to the Multifactorial models. First, patients with missing data on candidate variables were deleted [C-C model]. Then, applying Multivariable Imputation via Chained Equations [MICE], missing data were imputed. Logistic regression was fitted to C-C and imputed data sets [MICE model]. Models were compared in terms of number of variables retained in the final model, width of confidence intervals, and discrimination ability. About 22% of data were lost in C-C model. Number of variables retained in the C-C and MICE models was 2 and 6 respectively. Confidence Intervals [C.I.] corresponding to C-C model was wider than that of MICE. The MICE model showed greater discrimination ability than C-C model [70% versus 64%]. The C-C analysis resulted to loss of power and wide CI's. Once missing data were imputed, more variables reached significance level and C.I.'s were narrower. Therefore, we do recommend the application of the imputation method for handling missing data

main non clinical risk factors of major thalassemia in Fars provin

Thalassemia major is one of the most common genetic blood disorders that passes from parents to children. Since Fars province is one of the most common locations of thalassemia in our country. It seems that the present study can be helpful by identifying main non-clinical factors of the disease. This cross sectional study was done on registered data of less than 12 year old major thalassemia patients in Fars province by census method in 1997-2010. Underlying causes of thalassemia are divided into three groups: S[1] cases due to hardware problems, S[2] cases due to parents carelessness without having a history, and S[3] patients born to parents who married when genetic tests were not routine. Data were analyzed by using SPSS 16 and ANOVA tests. Analysis showed that S[1] with 48 persons [15.38%] with the mean age of 5.6 +/- 3.2, S[2] with 71 persons [22.75%] with the mean age of 6.8 +/- 1.2, and S[3] with 193 person [61.85%] with the mean age of 8.8 +/- 3.30 were the main groups of thalassemia .The least incidence rate was 0.13 per 10000 in 2010. With identifying the main underlying causes of major thalassemia regardless of its main cause which is herediatry from parents, considering levels and different consequences of these causes, and high efficiency of genetic tests before marriage, effective steps can be taken to reduce health-social and economic problems of thalassemia

prevalence of labyrinthine fistula in chronic otitis media surgery in Shiraz, Southern Iran

The incidence of fistulas found during the surgery for chronic otitis media with cholesteatoma has been reported in a wide range in different geographical areas. This study aims to find the prevalence of labyrinthine fistula in the south of Iran. A prospective cross sectional study of 787 [504 ears belong to 462 patients] consecutive tympanoplasty with or without mastoidectomy for chronic otitis media was performed. Data on preoperative clinical and preoperative and postoperative hearing status and intraoperative findings were analyzed. A labyrinthine fistula was found at surgery in 24 [4.7%] ears of the total 504 ears belonging to 462 patients undergoing surgery for chronic otitis media. Location of the fistula was the lateral semicircular canal in 23, posterior semicircular canal in 1 and promontory in 1 subject. There was a statistically significant difference in preoperative and postoperative AC threshold in 500-3000 Hz frequency and ABG 500-3000 Hz, but there was no statistically significant difference in the other variables. Regarding postoperative hearing outcome in the labyrinthine fistula surgery, it seems that there is no universal method of reporting of hearing results. Past hearing evaluation methods in the literature have been often poorly comparable, based on different methodology

comparison of prevalence of diabete and hypertension between rural areas of Fars and rural area of EMRO region

Since monitoring and evaluation of diabetes and hypertension in individuals/the population greatly contribute to improving both clinical care and following identification of disease in the region and even the country, and to manage prevent and control diabetes and hypertension and their risk factors, the goal of this study was to compare disease status in rural areas of Fars province and rural areas of the EMRO region. The current study is a descriptive-analytic cross sectional one that has been conducted in 2008 by randomized cluster sampling, based on data obtained from an extensive provincial screening plan for adults aged over 30 years in rural areas of Fars province. Based on these data, the prevalence of diabetes, hypertension and their risk factors were calculated and the relationship between diabetes and hypertension was determined by risk factors including age, sex, family history, and Ml using Chi square and t-test and SPSS software version 17 and Minitab version, prevalences in 15 is rural areas were compared with the ones in EMRO region countries. The prevalence of hypertension and diabetes rural areas of Fars province were calculated to be 21.8% and 11.14% respectively as compared with rural areas of EMRO region countries.The prevalence of diabetes was also lower on the average and the prevalence of obesity [BMI>30], was less than other countries in the region and Iran. In general, although, the prevalence obtained in this study was lower than other regional countries, raising a wareness in high rish groups affected public commitment to basic information transmitting to high risk classes of the society should be taken into account and commitment by the health system administration and the government to sustain monitoring of health, to ensure curtailing the burden of diabetes and hypertension and associated risk factors among countries of the region

Step by step clinical diagnosis. A 59 year old man with episodes of jaundice, anemia and repeated transfusions

A 59 Businessman presented to private clinic in Mashhad with one-week history of jaundice, anemia, weakness and vertigo. He reported having had dark urine, loss of appetite and tiredness. This man was a proved Case of PNH since 9 years, and he had been on predniselone 30 mg every other day. When the diagnosis of PNH by Ham test and Sugar test was confirmed and a bone marrow aspiration showed no severe abnormality except Hyperplasic B.M. Because of severe hemolytic anemia he received several times blood transfusion. In many developing countries, one of the primary routes of HCV infection is post blood transfusion. In spite of transfusion of screened blood products. In screening the patient for viral Hepatitis, HBsAg and anti HBC markers were negative but HCV antibody by 3ed generation Elisa assay was positive. A quantitative HCV PCR assay was positive with more than 12 million Virus copies per ml, Liver function tests were high [ALT and SLT]. Ultrasonography of liver showed a fatty liver without symptoms of portal Hypertension and ascitis. Pegasys [Peg interferon alpha -2 alpha Roche] with 180 mcgr. per week started but because of declining platelets, Neutrophyls and Hb after 4 injections, the peg interferon dosage was decreased to 135 mcgr per week and after 20 weeks to 90 mcgr per week. In spite of decreasing peg-interferon dosage, the number of platelets and neutrophils were under normal limit. Because of hemolytic side effect of Ribaverine we did not, prescribe this drug. In another HCV-PCR assay, it was strongly positive and liver enzymes were high, and PT was 19 seconds despite of injection Vit K and infusion of [factors 8 and 9] FFP, Prothrombin time did not change. The patient in a trip to Paris in Necker hospital was evaluated again and a transjugular liver biopsy was done. The report of liver pathologist of Necker Hospital by Metavir scoring was: A[1] F[2] and by Knodell scoring was: 0+1+1+1. So peg interferon discontinued and a complete check up of patient after Peg interferon D.C, evaluated a good condition. Liver enzymes were at normal range, total Bilirubin, less than 3 mg, WBC at a normal range, and no hemorrhagic abnormality. The patient now is in Mashhad with a good condition in spite of HCV-PCR positive. He is on a monthly clinical and laboratory surveillance and probably second liver biopsy should be done after one-year interval