Diagnostic Value of Radiographic Singh Index Compared to Dual-Energy X-Ray Absorptiometry Scan in Diagnosing Osteoporosis: A Systematic Review

Since various medications can control the rate of fractures and subsequent complications of osteoporosis, the early detection of the disease is crucial. This systematic study aimed to compare the diagnostic accuracy of Singh index (SI) with dual-energy X-ray absorptiometry (DEXA) as a benchmark standard for diagnosing osteoporosis.

The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) were utilized in the current study. A detailed search was carried out using PubMed and Scopus from inception to 30 May 2022. Examining quality of the studies was performed by the Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2).

A total of 22 studies were included. In general, 50% of the studies considered SI a poor screening tool for detecting osteoporosis due to a negligible inter-observer agreement between SI and DEXA or a poor correlation of SI with the bone mineral density (BMD) category or DEXA T-score. A moderate inter-observer agreement was reported for SI in 5 (55.6%) studies. Among the studies assessing the sensitivity and specificity of SI compared to DEXA (n=13), six studies estimated a low sensitivity for SI.

While there is supporting evidence indicating the potential usefulness of SI for predicting femoral neck fractures in individuals with suspected osteoporosis, numerous studies challenge its reliability and diagnostic value as a screening tool for identifying femoral neck osteoporosis. Further primary studies are required to verify the effectiveness of the SI index in identifying populations at risk of osteoporosis. Level of evidence: V