Can a drug duo rebuild bone in men better than one?

Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.

Inclusion Criteria: * DXA BMD T-score \< or = -2.0 at either lumbar spine (LS), femoral neck (FN) or total hip (TH) sites; or DXA BMD T-score \< or = -1.5 with at least one additional important clinical risk factor for osteoporotic fracture \[e.g., fragility fracture after age 50 years; parental history of hip fracture; history of hypogonadism, prior glucocorticoid therapy (\>3 months prior), current smoking, prevalent vertebral fracture(s), or prior hyperthyroidism on stable treatment\] * At least 2 LS vertebral levels with reliable BMD values (i.e., at least 2 without compression or hardware) Exclusion Criteria: * Metabolic bone disease other than osteoporosis (e.g., Paget's disease, hyperparathyroidism) * Any osteoporosis drug therapy within 12 months; any prior course of TPTD for \> or = 3 months; any history of IV bisphosphonate therapy; oral bisphosphonate therapy exceeding 3 months in past 2 years; oral bisphosphonate treatment exceeding 2 years ever; or use of denosumab (within the past 3 years or \> 3 or = injections ever). * Oral glucocorticoid use (\> or = 5 mg prednisone) taken within 3 months prior to enrollment * Hypercalcemia (albumin-corrected serum \[Ca\] \>10.2 mg/dL), hypocalcemia (albumin-corrected serum \[Ca\] \<8.8 mg/dL), elevated intact PTH level, or hypercalciuria (urinary Ca \>300 mg/24 hours) at screening * 25 OH vitamin D levels \<20 ng/ml or \>80 ng/ml at screening * Estimated glomerular filtration rate \< 30 ml/min (chronic kidney disease (CKD) stage 4 or 5) * Cancer within past 5 years except for non-melanomatous skin cancers * History of skeletal radiation, prior history of osteosarcoma or bone metastases * Substance abuse (\>3 drinks/day), liver disease or impaired liver function (abnormal liver function tests defined as greater than 3 times the upper limit of normal), known cirrhosis, malabsorption * Poorly controlled diabetes (A1c \>9.0%) or current thiazolidinedione therapy * Drugs metabolized through CYP2D6 (e.g., flecainide, tricyclic antidepressants) and strong inducers or inhibitors of CYP3A4 (e.g., itraconazole, ketoconazole) * Testosterone therapy with dose change within last 12 months; or androgen deprivation therapy within 12 months * Thyrotropin (TSH) level \< 0.01 * Congenital long QT syndrome, history of QT interval prolongation, family history of long QT syndrome or sudden cardiac death, and other conditions that predispose to QT interval prolongation and ventricular arrhythmia * Hypersensitivity to teriparatide or any excipients in Forteo * Use of other Ca-lowering drugs (e.g., calcitonin, bisphosphonates, denosumab) * Moderate to severe hepatic impairment * High risk for active urolithiasis, defined as having passed a kidney stone clinically within the last 5 years * Upper gastrointestinal (GI) bleeding with a history of a clinical episode of upper GI bleeding within last 10 years that was note definitively treated by a surgical procedure * Orthostatic hypotension or a known history of orthostatic hypotension documented in the chart or provided by the patient upon clinical history-taking * Impaired cardiac function either diagnosed symptomatic heart failure requiring medical therapy