The medication-based Rx-Risk Comorbidity Index and risk of hip fracture - a nationwide NOREPOS cohort study.

BACKGROUND: Few previous studies have assessed overall morbidity at the individual level with respect to future risk of hip fracture. The aim of this register-based cohort study was to examine the association between morbidity measured by the medication-based Rx-Risk Comorbidity Index (Rx-Risk) and the risk of first hip fracture. METHODS: Individual-level data on medications dispensed from pharmacies (2005-2016) was retrieved from the Norwegian Prescription Database and used to calculate Rx-Risk for each calendar year. Information on first hip fractures (2006-2017) was obtained from a nationwide hip fracture database. Individuals ≥ 51 years who filled at least one prescription during the study period comprised the population at risk. Using Rx-Risk as a time-varying exposure variable, relative risk estimates were obtained by a negative binomial model. RESULTS: During 2006-2017, 94,104 individuals sustained a first hip fracture. A higher Rx-Risk was associated with increased risk of hip fracture within all categories of age and sex. Women with the highest Rx-Risk (> 25) had a relative risk of 6.1 (95% confidence interval (CI): 5.4, 6.8) compared to women with Rx-Risk ≤ 0, whereas the corresponding relative risk in women with Rx-Risk 1-5 was 1.4 (95% CI: 1.3, 1.4). Similar results were found in men. Women > 80 years with Rx-Risk 21-25 had the highest incidence rate (514 (95% CI: 462, 566) per 10, 000 person years). The relative increase in hip fracture risk with higher Rx-Risk was most pronounced in the youngest patients aged 51-65 years. CONCLUSIONS: Rx-Risk is a strong predictor of hip fracture in the general outpatient population and may be useful to identify individuals at risk in a clinical setting and in future studies.

Educational gradient in hip fracture incidence in Norway. The Norwegian Epidemiologic Osteoporosis Studies (NOREPOS).

Examining fracture dynamics by socioeconomic status may inform healthcare and prevention. We found a higher risk of hip fracture in men and women with lower educational level in Norway. However, by age 90 + years, the cumulative incidence was higher in those with higher education, due to their higher life expectancy. PURPOSE: Socioeconomic gradients are seen for several health outcomes in high-income countries. We aimed to examine possible educational gradients in risk of hip fracture in Norway and to describe the cumulative incidence of hip fracture by educational level. METHODS: In a population-wide cohort of Norwegians aged ≥ 50 years, information on attained education from Statistics Norway was linked to hospital-treated hip fractures and deaths during 2002-2019. We estimated relative fracture risk by educational level (primary, secondary or tertiary) in Cox proportional hazards regression. We also examined the cumulative incidence over attained age by gender and educational level in competing risk regression. RESULTS: The population included N = 1,389,858 individuals with 135,938 incident hip fractures. Compared with men who had attained tertiary education, hazard ratios (95% confidence intervals) for hip fracture were 1.44 (1.40, 1.49) in men with primary education only and 1.26 (1.22, 1.29) in men with secondary education. In women, the corresponding estimates were 1.28 (1.25, 1.31) and 1.16 (1.13, 1.19). In the age range 50 to 90 years, the highest cumulative incidence of hip fracture was seen in those with primary education. The gradient gradually diminished with advancing age and was reversed in the oldest (> 90 years) in both genders. CONCLUSIONS: There was a clear educational gradient in hip fracture incidence in both men and women in Norway, with a higher risk in people with lower education. Despite this, the cumulative incidence of hip fracture in old age was highest among people with higher education, due to their higher life expectancy.

Cause-specific excess mortality after hip fracture: the Norwegian Epidemiologic Osteoporosis Studies (NOREPOS).

BACKGROUND: Information on cause of death may help appraise the degree to which the high excess mortality after hip fracture reflects pre-existing comorbidities or the injury itself. We aimed to describe causes of death and cause-specific excess mortality through the first year after hip fracture. METHODS: For studying the distribution of causes of death by time after hip fracture, we calculated age-adjusted cause-specific mortality at 1, 3, 6 and 12 months in patients hospitalized with hip fracture in Norway 1999-2016. Underlying causes of death were obtained from the Norwegian Cause of Death Registry and grouped by the European Shortlist for Causes of Death. For estimating excess mortality, we performed flexible parametric survival analyses comparing mortality hazard in patients with hip fracture (2002-2017) with that of age- and sex matched controls drawn from the Population and Housing Census 2001. RESULTS: Of 146,132 Norwegians with a first hip fracture, a total of 35,498 (24.3%) died within one year. By 30 days post-fracture, external causes (mainly the fall causing the fracture) were the underlying cause for 53.8% of deaths, followed by circulatory diseases (19.8%), neoplasms (9.4%), respiratory diseases (5.7%), mental and behavioural disorders (2.0%) and diseases of the nervous system (1.3%). By one-year post-fracture, external causes and circulatory diseases together accounted for approximately half of deaths (26.1% and 27.0%, respectively). In the period 2002-2017, cause-specific one-year relative mortality hazard in hip fracture patients vs. population controls ranged from 1.5 for circulatory diseases to 2.5 for diseases of the nervous system in women, and correspondingly, from 2.4 to 5.3 in men. CONCLUSIONS: Hip fractures entail high excess mortality from all major causes of death. However, the traumatic injury of a hip fracture is the most frequently reported underlying cause of death among older patients who survive less than one year after their fracture.

Forearm fractures - are we counting them all? An attempt to identify and include the missing fractures treated in primary care.

OBJECTIVE: Norway has a high incidence of forearm fractures, however, the incidence rates based on secondary care registers can be underestimated, as some fractures are treated exclusively in primary care. We estimated the proportion of forearm fracture diagnoses registered exclusively in primary care and assessed the agreement between diagnosis for forearm fractures in primary and secondary care. DESIGN: Quality assurance study combining nationwide data from 2008 to 2019 on forearm fractures registered in primary care (Norwegian Control and Payment of Health Reimbursement) and secondary care (the Norwegian Patient Registry). SETTING AND PATIENTS: Forearm fracture diagnoses in patients aged ≥20 treated in primary care (n = 83,357) were combined with injury diagnoses for in- and outpatients in secondary care (n = 3,294,336). MAIN OUTCOME MEASURES: Proportion of forearm fractures registered exclusively in primary care, and corresponding injury diagnoses for those registered in both primary and secondary care. RESULTS: Of 189,105 forearm fracture registrations in primary and secondary care, 13,948 (7.4%) were registered exclusively in primary care. The proportion ranged from 4.9% to 13.5% on average between counties, but was higher in some municipalities (>30%). Of 66,747 primary care forearm fractures registered with a diagnosis in secondary care, 62% were incident forearm fractures, 28% follow-up controls, and 10% other fractures or non-fracture injuries. CONCLUSION: An overall small proportion of forearm fractures were registered only in primary care, but it was larger in some areas of Norway. Failing to include fractures exclusively treated in primary care could underestimate the incidence rates in these areas.

Norwegian forearm fracture incidence based on secondary care may be underestimated by not including fractures treated exclusively in primary care.The mean proportion of forearm fractures exclusively handled in primary care is 7% and varies from 5% to 14% between counties.Fractures treated in primary care can be considered for more accurate national incidence rates. Correct fracture diagnosis needs further investigation.