“…The potential confounding factors in this study were mainly determined according to Japanese 2011 guidelines for prevention and treatment of osteoporosis. [ 16 , 23 – 26 ] The following baseline comorbidities were identified according to diagnoses in the claims records data before the index date: hypertension (ICD-9-CM codes 401–405), diabetes mellitus (ICD-9-CM code 250), hyperlipidaemia (ICD-9-CM code 272), chronic kidney disease (ICD-9-CM code 582,583,585,586 and 588), chronic liver disease (ICD-9-CM code 456, 571 and 572), chronic obstructive pulmonary disease (ICD-9-CM code 491, 492, 494 and 496), depression (ICD-9-CM code 296.2, 296.3, 300.4 and 311). The Charlson comorbidity index (CCI) scores, categorised into four levels (0, 1–2, 3–4 and ≥5), were used to assess the severity of co-morbidities, which included myocardial infarction, congestive heart failure, peripheral vascular disease, cerebrovascular disease, dementia, chronic pulmonary disease, rheumatic disease, peptic ulcer disease, mild and moderate or severe liver disease, diabetes with and without chronic complication, hemiplegia or paraplegia, renal disease, any malignancy (including lymphoma and leukemia, except malignancy of skin), metastatic solid tumor, human immunodeficiency virus infection and acquired immune deficiency syndrome.…”