Interobserver and intraobserver agreement in radiographic diagnosis of osteoporosis

ABSTRACT

Osteoporosis is a common bone disorder which means paucity of bone particularly of trabecular bone. This leads to increased tendency to fractures and bone pains. The radiological diagnostic workup usually starts from plain x-rays followed by bone mass measurement techniques. To determine the inter- and intra-observer agreement in plain x-ray diagnosis of osteoporosis using a standardized grading system. It was a cross-sectional analytical study conducted from May 2004 to June 2005 at Radiology department Dow University of Health Sciences and Civil Hospital, Karachi and Osteoporosis Diagnostic Clinic Karachi. Plain non digital x-rays of femur of post menopausal females [a group known to be at risk of and clinically suspected with osteoporosis] were independently read by three qualified professionals-two radiologists and a nuclear physician specialized in osteoporosis diagnosis. Standardized radiological grades of osteoporosis [Singh Index] were assigned to plain x-rays of pelvis and femur. Kappa statistics were used to determine inter- and intra-observer agreement by computing k-value. A total of 98 patients were included in the study. All were post menopausal females with age of 59 +/- 6.5 years Kappa [k-] value for inter-observer agreement ranged from 0.21 to 0.44. For intra-observer agreement, it was 0.69 to 0.78. The inter- and intra-observer agreement for diagnosis of osteoporosis on plain x-rays alone is markedly low, necessitating the use of multiple and sensitive techniques rather than plain x-rays alone