Global Journal of Medical Research, F: Diseases, Volume 22 Issue 6

CF is a disease of white populations, so rarely suspected and diagnosed. But recent review of different published studies, reports and comments indicate that the presence of CF among the people in the Indian sub- continent is much more than previous thinking and the disease is under-diagnosed or missed in the majority of cases. 10 To our knowledge, till to date, there is no well accepted diagnostic procedure and structured management protocol for CF in Bangladesh. The present study was designed to introduce the pilocarpine iontophoresis sweat chloride test using an indigenously developed and validated equipment for accurate and inexpensive diagnosis of CF for the first time in Bangladesh and to determine the phenotypic spectrum of CF for raising the physician’s awareness about the disease in this country. II. M aterials and M ethods a) Study design and setting This prospective observational study was conducted over 3 years from January 2017 to December 2019 in the National Institute of Diseases of the Chest and Hospital (NIDCH), the largest respiratory care hospital and academic institute in government level in Bangladesh, in collaboration with Ibn Sine Hospital and Diagnostic Centre, a tertiary level referral Centre in Dhaka, the capital city of Bangladesh. The study was approved by the institutional review board. b) Study population and sampling procedure A total of 400 patients suspected of CF- having respiratory and/or GI symptoms, features of FTT, were included in the study regardless of age, sex and socioeconomic status with strictly following the inclusion and exclusion criteria. The majority of these patients were referred from different hospitals and medical centers of the country for proper diagnosis and better management. A detailed history and thorough clinical examinations were done. Proper investigations for individual patients were advised. All patients or parents provided written consent prior to study commencement and the sweat chloride test was described individually. The clinical features, presence of one or more, considered as criteria to include the patient in the study to undergo sweat chloride test by pilocarpine iontophoresis were – recurrent respiratory tract infections, recurrent/persistent pneumonia, history of CF in siblings, ch malabsorption, steatorrhea, failure to thrive, nasal polyps, rectal prolapse, bronchiectasis in radiology. Patients having clinical and/or laboratory findings suggestive of tuberculosis, bronchial asthma, cong. heart disease, lactose intolerance were excluded from the study. c) Sweat testing Sweat chloride tests (SCT) were done by an indigenously developed and validated equipment 11 using low-cost technology. It’s a very useful and inexpensive method for sweat collection and chloride estimation in resource poor settings for CF diagnosis (video -1). Sweat collection was done by pilocarpine iontophoresis following Gibson and Cooke method 12 and quantitative chloride estimation in collected sweat, minimum 100 mg collected within 30 minutes, was done by Schales and Schales method 13 and labelled as follows: Cystic Fibrosis– Is it Extremely Rare or Invariably Missed: An Observational Study in Bangladesh Scenario 20 Year 2022 Global Journal of Medical Research Volume XXII Issue VI Version I ( D ) F © 2022 Global Journals The concentration of Chloride (Cl-) Indicator < 29 mEq/L normal 30- 59 mEq/L borderline >60 mEq/L positive 14 Validation of the SCT results were done periodically by performing chloride estimation on known strength of saline solution. The mean and standard deviation of the difference from the standard was calculated and 95% confidence interval was estimated. Sweat chloride tests were repeated at least one week apart in cases of positive or borderline results. Patients with normal sweat tests were properly evaluated to come to a diagnosis excluding possible differentials. Patients with borderline sweat test results were treated according to the clinical ground and subsequently prepared for mutation analysis. d) Statistical analysis Descriptive analyses were performed using frequency, percentage and mean with standard deviation (SD). Figures in the parenthesis indicate the corresponding percentage. Comparisons were made using the Chi-square test for categorical variables. A p- value of <0.05 was considered as the level of significance. All the statistical analyses were conducted using Stata 16. e) Ethical consideration Ethical approval was obtained from the Institutional Review Board (IRB) of both centers (NIDCH/EC/09-2017). Informed written consent and with ascent was taken from each patient or their parents prior to study commencement. Confidentiality and anonymity of the patients were ensured. The sweat chloride test procedure as well as its potential benefit and risks were individually described to the patients and participation was voluntary where the participants had the right to withdraw at any time during the study. In case of refusal/non-response, no discrimination was done. Finally, no financial incentive or compensation was provided to the participants. III. R esults Out of 400 patients having clinical suspicion of CF and underwent pilocarpine iontophoresis, the test was positive in 38 patients (9.5%) and borderline in 9 patients (2.25%) on two occasions at least one week apart. The