Understanding the predictive accuracy of the InsuTAG index over other surrogate indices in normoglycaemic, non-obese males from Southern India.

We aimed to evaluate the predictive accuracy of InsuTAG index against M value of the hyperinsulinaemic-Euglycaemic clamp (HEC) procedure and fasting surrogate indices of insulin sensitivity/resistance in young, normoglycaemic, Asian Indian males. HEC studies were done in young (mean age 19.7 ± 1 years), non-obese (mean BMI 19.2 ± 2.6 kg/m2), normoglycemic Asian Indian males (n = 110) and the M value was calculated. Surrogate indices namely InsuTAG index, HOMA-IR, FG-IR, QUICKI and McAuley index were calculated. Pearson's correlation and ROC-AUC at 95% CI were applied. Significant negative correlation was observed for InsuTAG index with the M value (r - 0.23, p = 0.01), McAuley index (r - 0.65, p < 0.01), QUICKI (r - 0.34, p < 0.01) and FGIR (r - 0.35, p < 0.01). Significant positive correlations of InsuTAG index were observed for BMI and waist circumference. The ROC-AUC was higher for InsuTAG index (0.75) than FGIR (0.30), QUICKI (0.31), and McAuley index (0.20). The InsuTAG cut-off value ≥ 19.13 showed 66.7% sensitivity and 69.2% specificity in this study group.

Tenofovir-induced hypophosphatemic osteomalacia: how do bone mineral density, trabecular bone score and proximal hip geometry change with treatment?

Summary: Tenofovir-induced osteomalacia secondary to proximal renal tubular dysfunction is not an uncommon complication known to occur. A 46-year-old woman was referred for the evaluation of osteoporosis which was diagnosed elsewhere. She had polyarthralgia, bony pains and proximal muscle weakness of 1 year duration. She was diagnosed to have HIV infection and was on antiretroviral therapy that consisted of tenofovir, lamivudine and efavirenz for the past 12 years. She had attained menopause 5 years back. On examination, she had bone tenderness, proximal myopathy and painful restriction of movement of her lower limbs. Investigations showed features of renal tubular acidosis, hypophosphatemia and raised alkaline phosphatase that were suggestive of osteomalacia. X-ray of the pelvis showed diffuse osteopenia and an MRI of the pelvis done showed multiple insufficiency fractures involving the head of femur on both sides. Following this, her tenofovir-based regimen was changed to abacavir, efavirenz and lamivudine with addition of neutral phosphate supplements and calcitriol. On follow-up after 6 months, she had significant improvement in her symptoms as well as in the bone mineral density at the lumbar spine (33.2%), femoral neck (27.6%), trabecular bone score (13.2%) and reduction in the buckling ratio at the narrow neck (6.3%), inter-trochanteric region (34%) and femoral shaft (28.8%). Tenofovir-induced osteomalacia is encountered in individuals on prolonged treatment with tenofovir. Treatment consists of changing to a non-tenofovir-based regimen, as well as supplementation of phosphate and calcitriol. Treatment results in remarkable improvement in symptoms and most densitometric indices. Learning points: Tenofovir is a nucleotide reverse transcriptase inhibitor (NRTI) and is a major drug in the treatment of retroviral and hepatitis B infections. Tenofovir-related hypophosphatemic osteomalacia is related to proximal tubulopathy and is not an uncommon occurrence. Treatment mandates changing to a non-tenofovir-based regimen with supplementation of neutral phosphate and calcitriol. Treatment results in a significant improvement in bone mineral density, trabecular bone score and hip geometric parameters.

Bisphosphonate-induced atypical femoral fracture in tandem: long-term follow-up is warranted.

Summary: Although bisphosphonates (BPs) are mainly used for the treatment of osteoporosis and are generally safe, long-term use and more dosage as utilised in malignant conditions may be associated with the rare adverse event of an atypical femoral fracture (AFF). Occasionally, the risk of developing an AFF persists long after BPs are withdrawn. A 39-year-old woman who underwent chemotherapy and an autologous stem cell transplantation for multiple myeloma presented to us with history of pain in the left thigh. She had received multiple doses of oral and parenteral BPs for about 10 years in view of the underlying myeloma with osteoporosis. Her investigations showed a suppressed CTX of 192 pg/mL, and radiograph of pelvis displayed thickened cortices with beaking of the left femoral shaft, which was suggestive of an AFF. Following discontinuation of BPs, she underwent prophylactic intra-medullary nailing with which her symptoms improved. Five years later, she presented with similar complaints on the right side. Investigations showed that her bone turnover continued to be suppressed with Cross linked C- Telopeptide of type 1 collagen (CTX) of 165 pg/mL and an X-ray done showed AFF on the right side despite being off BPs. A second intra-medullary nailing was done and on follow-up, she has been symptom-free and independent in her daily activities. Discontinuation of BPs may not prevent the incident second AFF and, therefore, thus warranting long-term follow-up. Learning points: Regular screening and follow-up of patients who receive long-term bisphosphonate (BP) therapy should be done. Discontinuation of BPs does not preclude the possibility of repeated occurrence of a second AFF. Long-term BP therapy warrants regular monitoring and follow-up should an AFF occur.

Impact of teriparatide therapy in Indian postmenopausal women with osteoporosis with regard to DXA-derived parameters.

Background: There is paucity of literature on the impact of teriparatide on hip geometry and bone microarchitecture globally and none from the Indian subcontinent. This study examined the outcome of teriparatide therapy on vertebral fractures, bone mineral density (BMD), hip structural analysis (HSA), and trabecular bone score (TBS) in Indian postmenopausal women with severe osteoporosis. Methodology: Ambulatory postmenopausal women above the age of 50 years with either severe osteoporosis or vertebral fractures, or both, were recruited. All patients received cholecalciferol (2000 IU/day), calcium carbonate (elemental calcium 1 g/day), and teriparatide (20 mcg subcutaneously/day) for 24 months. Baseline bone biochemistry, BMD, TBS, and HSA were assessed and repeated after 24 months of therapy. Incident vertebral and nonvertebral fractures were also studied. Results: A total of 51 postmenopausal women with mean (SD) age of 65.7(8.6) years, and mean (SD) body mass index of 22.7 (3.5) kg/m2 were recruited in this study. Vertebral fractures were present in 74.5% (38/51) at baseline. Following teriparatide therapy, significant improvement was observed in the BMD (g/cm2) at both the lumbar spine (0.706-0.758: p < 0.001) and femoral neck (0.551-0.579: p = 0.047) as well as the TBS (1.160-1.271: p < 0.001). Most indices of proximal hip geometry also showed significant improvement following teriparatide therapy at 24 months. Incident vertebral fractures were noted in only 7.8% (4/51) of participants, while 92% (47/51) of participants did not develop any new vertebral fractures on follow-up. Conclusion: In South Indian postmenopausal women with either severe osteoporosis or vertebral fractures, or both, teriparatide was effective in improving the bone mineral parameters and bone quality.