Principal Investigator Chest Radiographs and their reliability in the diagnosis of Tuberculosis Principal Investigator Dr. Narayan Kumar T.B. Specialist & Hospital Director, BPKIHS Co Investigators Prof. S.K. Bhargava, Prof. Kuryan George, Prof. C.S. Agrawal, Dr. Prahlad Karki, Mr. Dharanidhar Baral, BPKIHS

Objectives To see the reliability in diagnosis of tuberculosis by X-ray in context of our country doctor, radiologist, physicians of different level.

Material & Method Study site:- Tuberculosis Clinic of the BPKIHS. A 700 bed teaching hospital. Tuberculosis Lab Present with fluorescent microscopy and culture facilities.

Method 75 radiographs of following diagnosis Sputum +ve Healed tuberculosis Pleural effusion Non tuberculosis lung lesion Healthy patient (normal CX) The diagnosis was arrived after review by expert of panel which included Radiologist Surgeon Physicians

Reference for panel was on the following basis:- Radiological finding Bacteriological finding Response to anti TB chemotherapy The diagnosis made by panel on above criteria was considered – the “Gold standard” for further analysis.

Qualification of doctor MD Internal Medicine MS General Surgery MS Obs/Gynae MD Radiodiagnosis MBBS Question A format to locate the lesion Diagnosis choice Active TB Inactive TB Healed TB Non tuberculous Normal The findings were compared against the gold standard.

Age-Gender distribution of 25 doctors. Results Age-Gender distribution of 25 doctors. Age -group In Years Gender Total Male Female 25-29 5(22.7) 3(100) 8(32) 30-34 11(50) 11(44) 35-39 2(9.1) 2(8) 40-44 45+ 22 3 25

Year of passing MBBS Year No. (%) <1970 2(8) 1970-1980 1(4) 1981-1990 5(20) > 1990 17(68) Total 25

No of Radiographs seen /day by a doctor No. of Radiographs/day No.(%) <=10 5(20) 11 –20 7(28) >=21 2(8) No response 11(44) Total 25

Validity of Chest x-ray in diagnosing tuberculosis Diagnosis by Physician True diagnosis Total Tb No Tb 1191 172 1363 334 178 512 1525 350 1875 Sensitivity : 78.1% Specificity : 50.9%

Validity of Chest x-ray in diagnosing active tuberculosis Diagnosis by Physician True diagnosis Total Tb No Tb 597 245 842 403 630 1033 1000 875 1875 Sensitivity: 59.7% Specificity: 72%

Score of physicians in reading Chest Radiographs Overall (n=25) Postgraduates (n=13) MBBS (n=12) Maximum 54 39 Minimum 22 33 Mean 35.8 36 32 Median 35 43 31.4

Physician’s diagnosis Agreement between physician and radiologist Diagnosis by Radiologist Physician’s diagnosis Total Correct Wrong 34 20 54 9 12 21 43 32 75 K = 0.17(0-0.38) *figures in parenthesis indicate the 95% CI

Conclusion Unsatisfactory sensitivity and specificity. Taking a factor of 2% population have TB and 5% have symptoms of TB, the predictive value among the symptomatic will only be about 60% and negative predictive value 72%. Physician would lead treating a large proportion of them unnecessarily.

Over diagnosis is followed by over treatment :- unmanageable burden on the health resources. The low sensitivity could also lead to under diagnosis and consequently deny of chemotherapy.

NTC or other stake holders in program should focus the message to the mass that x-ray is not important as the patient himself belief that x-ray is essential and the doctor also believe therefore the problem is doubled till date NTC is giving message to doctor but not accepted by the doctor, there is no attempt to give message to population about this fact.