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Biomedical subjects

A Oden

Publications and source records attributed to A Oden.

At least 37 records · Page 2Linked to original sources

Cost-effectiveness of preventing hip fracture in the general female population.

The aims of this study were to determine whether treatments that reduce the incidence of hip fracture might be used in the general female population rather than screening or case-finding strategies. Cost-effectiveness, measured as cost per quality-adjusted life-year (QALY) gained using threshold values for cost-effectiveness of $20,000 or $30,000/QALY gained, was assessed during and after treatment using a computer simulation model applied to the female population of Sweden. The base case assumed a 5-year intervention that reduced the risk of hip fracture by 35% during the treatment period, and an effect that reversed to the pretreatment risk during the next 5 years. Sensitivity analyses included the effects of age, different treatment costs and effectiveness. Cost-effectiveness was critically dependent upon the age and costs of intervention. Reasonable cost-effectiveness was shown even with relatively high intervention costs for women at average risk at the age of 84 years or more. For the cheapest interventions ($63/year) cost-effectiveness could be found from the age of 53 years. Variations in effectiveness (15-50% risk reduction) had marked effects on the age that treatment was worthwhile. We conclude that segments of the apparently healthy population could be advantaged by treatment if efficacy were supported by randomized controlled studies.

Age Factors↗

The burden of osteoporotic fractures: a method for setting intervention thresholds.

The aim of this study was to assess the relationship between morbidity from hip fracture and that from other osteoporotic fractures by age and sex based on the population of Sweden. Osteoporotic fractures were designated as those associated with low bone mineral density (BMD) and those that increased in incidence with age after the age of 50 years. Severity of fractures was weighted according to their morbidity using utility values based on those derived by the National Osteoporosis Foundation. Morbidity from fractures other than hip fracture was converted to hip fracture equivalents according to their disutility weights. Excess morbidity was 3.34 and 4.75 in men and women at the age of 50 years, i.e. the morbidity associated with osteoporotic fractures was 3-5 times that accounted for by hip fracture. Excess morbidity decreased with age to approximately 1.25 between the ages of 85 and 89 years. On the assumption that the age- and sex-specific pattern of fractures due to osteoporosis is similar in different communities, the computation of excess morbidity can be utilized to determine the total morbidity from osteoporotic fractures from knowledge of hip fracture rates alone. Such data can be used to weight probabilities of hip fracture in different countries in order to take into account the morbidity from fractures other than hip fracture, and to modify intervention thresholds based on hip fracture risk alone. If, for example, a 10-year probability of hip fracture of 10% was considered an intervention threshold, this would be exceeded in women with osteoporosis aged 65 years and more, but when weighted for other osteoporotic fractures would be exceeded in all women (and men) with osteoporosis.

Age Distribution↗

Acute and long-term increase in fracture risk after hospitalization for vertebral fracture.

The aims of this study were to determine the magnitude of the increase in risk of further fracture following hospitalization for vertebral fracture, and in particular to determine the time course of this risk. The records of the Swedish Patient Register were examined from 1987 to 1994 to identify all patients who were admitted to hospital for thoracic or lumbar vertebral fractures. Vertebral fractures were characterized as due to high- or low-energy trauma. Patients were followed for subsequent hospitalizations for hip fracture, and for all fractures combined. A Poisson model was used to determine the absolute risk of subsequent nonvertebral fracture and compared with that of the general population. We analyzed 13.4 million hospital admissions from which 28,869 individuals with vertebral fracture were identified, of which 60% were associated with low-energy trauma. There was a marked increase in subsequent incidence of hip and all fractures within the first year following hospitalization for vertebral fracture in both men and women. Thereafter, fracture incidence declined toward, but did not attain, baseline risk. Increased risks were particularly marked in the young. The increase in fracture risk was more marked following low-energy vertebral fracture than in the case of high-energy trauma. We conclude that the high incidence of new fractures within a year of hospitalization for vertebral fractures, irrespective of the degree of trauma involved, indicates that such patients should be preferentially targeted for treatment. It is speculated that short courses of treatment at the time of first vertebral fracture could provide important therapeutic dividends.

Acute Disease↗

Diagnosis of osteoporosis and fracture threshold in men.

This review examines the hypothesis that there are gender differences in the relationship between bone mineral density (BMD) and fracture risk. Prospective studies of spine and hip fracture risk drawn from population samples suggest that the fracture risk increases as BMD decreases in men in the same way as that described in women. Moreover, for any given BMD at the spine, heel, or proximal femur the risk in men is similar to that in women. Although data are limited, prior fragility fractures increase subsequent fracture risks in both men and women. These studies suggest that the same BMD criteria used to diagnose osteoporosis in women can be applied to men.

Absorptiometry, Photon↗

Targeting of hormone replacement therapy immediately after menopause.

The aim of this study was to model the effect of short (3-year) treatments with hormone replacement therapy (HRT) at the time of menopause on the risk of osteoporotic fracture, and to assess the impact of strategies to target high-risk individuals. From the relationship between bone mineral density (BMD) and fracture risk, treatment that increased bone mineral density at the hip by 6% over untreated women would save 35 vertebral, 62 hip, 13 proximal humeral, and 16 forearm fractures per 1000 women. The number needed to treat (NNT) to prevent one of these fractures was 8. The NNT fell modestly by targeting HRT to women with low bone mass or osteoporosis (NNT 6 and 5, respectively). The gains in fractures saved from targeting women with low bone mass or osteoporosis were offset by the requirement for assessment by BMD. Changes in the assumptions about the efficacy of HRT had a modest impact on fractures saved compared with the effect of changing assumptions concerning the offset of effect when treatment was stopped. We conclude that comparatively short courses of HRT might be effectively offered to all suitable women at menopause provided that the effects on bone persist when treatment is stopped.

Bone Density↗

Acute and long-term increase in fracture risk after hospitalization for stroke.

BACKGROUND AND PURPOSE: The aims of this study were to determine the magnitude of the increase in fracture risk after hospitalization for stroke, and in particular to determine the time course of this risk. METHODS: The records of the Swedish register of patients admitted during 1987-1996 were examined to identify all patients who were admitted to the hospital for stroke. Patients were followed for subsequent hospitalizations for hip and all fractures combined. We analyzed 16.3 million hospitalizations, from which 273 288 individuals with stroke were identified. A Poisson model was used to determine the absolute risk of subsequent fractures and the risk compared with that of the general population. RESULTS: After hospitalization for stroke, there was a >7-fold increase in fracture risk, including that for hip fracture within the first year after hospitalization for stroke. Thereafter, fracture risk declined toward, but did not attain, the baseline risk except in men and women aged >/=80 years. CONCLUSIONS: The high incidence of new fractures within the first year of hospitalization for stroke suggests that such patients should be preferentially targeted for treatment. It is possible that short courses of treatment at the time of stroke would provide important therapeutic dividends.

Acute Disease↗

Risk of hip fracture derived from relative risks: an analysis applied to the population of Sweden.

Bone mineral density measurements are widely used to estimate the relative risk of hip fracture. In addition, many other risk factors have been identified, some of which are known to add to the risk independently of other risk factors, including bone mineral density measurements. In this paper we develop an algorithm that converts relative risks for hip fracture to absolute (15 years and lifetime) risks, modeled on the population of Sweden. Lifetime risks increased as expected with increments in relative risk. Average lifetime risk in women at the age of 50 years was 22.7%, which increased to 64.9% when the relative risk was 6.0. In men the risk increased from 11.1% to 41.3%. The identification of high-risk groups had little effect on the specificity of assessments but increased the sensitivity over a wide range of assumptions. The increment in lifetime risk was relatively stable across all ages, reducing the complexity of computing lifetime risks from relative risk. The derivation of absolute risk from relative risk permits the optimization of selection of individuals or populations either for further risk assessment or for treatment.

Age Factors↗

Long-term risk of osteoporotic fracture in Malmö.

The objectives of the present study were to estimate long-term risks of osteoporotic fractures. The incidence of hip, distal forearm, proximal humerus and vertebral fracture were obtained from patient records in Malmö, Sweden. Vertebral fractures were confined to those coming to clinical attention, either as an inpatient or an outpatient case. Patient records were examined to exclude individuals with prior fractures at the same site. Future mortality rates were computed for each year of age from Poisson models using the Swedish Patient Register and the Statistical Year Book. The incidence and lifetime risk of any fracture were determined from the proportion of individuals fracture-free from the age of 45 years. Lifetime risk of shoulder, forearm, hip and spine fracture were 13.3%, 21.5%, 23.3% and 15.4% respectively in women at the age of 45 years. Corresponding values for men at the age of 45 years were 4.4%, 5.2%, 11.2% and 8.6%. The risk of any of these fractures was 47.3% and 23.8% in women and men respectively. Remaining lifetime risk was stable with age for hip fracture, but decreased by 20-30% by the age of 70 years in the case of other fractures. Ten and 15 year risks for all types of fractures increased with age until the age of 80 years, when they approached lifetime risks because of the competing probabilities of fracture and death. We conclude that fractures of the hip and spine carry higher risks than fractures at other sites, and that lifetime risks of fracture of the hip in particular have been underestimated.

Age Factors↗

Prediction of fracture from low bone mineral density measurements overestimates risk.

There is a well-established relationship between bone mineral density (BMD) and fracture risk. Estimates of the relative risk of fracture from BMD have been derived mainly from short-term studies in which the correlation between BMD at assessment and BMD in later life ranged from 0.8 to 0.9. Because individuals lose bone mineral at different rates throughout later life, the long-term predictive value of low BMD is likely to decrease progressively with time. This article examines and formalizes the relationship between current BMD, correlation coefficients, and long-term risk. The loss of predictive value has important implications for early assessment and supports the view that measurements should be optimally targeted at the time interventions are contemplated and, when necessary, repeated in later life.

Age Distribution↗

Risk of hip fracture according to the World Health Organization criteria for osteopenia and osteoporosis.

The risk of hip fracture is commonly expressed as a relative risk. The aim of this study was to examine the utility of relative risks of hip fracture in men and women using World Health Organization (WHO) diagnostic criteria for low bone mass and osteoporosis. Reference data for bone mineral density (BMD) at the femoral neck, from the third National Health and Nutrition Examination Survey (NHANES III), were applied to the population of Sweden. Relative risks (RRs) were calculated from the known relationship between BMD at the femoral neck and hip fracture risk. The apparent prevalence of low bone mass and osteoporosis depended on the segment of the young population chosen for reference ranges. Using a reference derived from women aged 20-29 years, the prevalence of osteoporosis was 21.2% in women between the ages of 50 and 84 years and 6.3% in men. The RRs associated with osteoporosis depended markedly on the risk comparison. For example, in men or women aged 50 years, the RR of hip fracture in those with osteoporosis compared to those without osteoporosis was 7.4 and 6.1, respectively. The RR of those at the threshold value for osteoporosis compared to those with an average value for BMD at that age was 6.6 and 4.6 in men and women, respectively. RRs were lower comparing those at the threshold value compared to the risk of the general population at that age (4.2 and 2.9, respectively). When RR was expressed in relation to the population risk rather than to the risk at the average value for BMD, RR decreased at all ages by 37%. Such adjustments are required for risk assessment in individuals and for the combined use of different risk factors. Because the average T score at each age decreased with age, the RR of hip fracture at any age decreased with advancing age in the presence of osteoporosis. The decrease in relative risk with age is, however, associated with an increase in absolute risk. Thus, for clinical use, the expression of absolute risks may be preferred to relative risks.

Adult↗

Effect and offset of effect of treatments for hip fracture on health outcomes.

We investigated the cost-effectiveness of treatments that reduce the risk of hip fracture using a computer simulation model. Cost-effectiveness was measured as cost per quality-adjusted life-year (QALY) gained using a threshold value for cost-effectiveness of $30,000/QALY gained. The baseline simulations assumed a 5-year intervention that reduced the risk of hip fracture by 50% during the intervention period, and an effect which reversed to the pretreatment risk during the next 5 years. Sensitivity analyses included the effects of age, different fracture risks, and different treatment costs and duration of therapeutic effect once treatment was stopped. Cost-effectiveness was critically dependent upon absolute risk determined by the age and the relative risk of hip fracture at any given age. Reasonable cost-effectiveness was shown even with relatively high intervention costs for women with a risk about twice the average at the age of 70 or more years. Cost-effectiveness was critically dependent upon the assumptions made concerning offset of effect of intervention after the end of treatment. Where no residual effect was assumed, it was difficult to show cost-effectiveness from any intervention except for the most effective and least expensive. Conversely, cost-effectiveness improved considerably where effectiveness persisted for a longer time. These studies support the view that intervention in the elderly with agents affecting skeletal metabolism alone may be preferred to such interventions at the time of the menopause, and that offset time, hitherto poorly characterized, is a critical component of cost-effectiveness, particularly in younger women.

Age Factors↗

Lifetime risk of hip fractures is underestimated.

Estimates of lifetime risk of osteoporotic fracture have assumed that mortality rates do not change. Since mortality in the elderly is decreasing in all regions of the world we assessed the effect of this on lifetime risks for hip fracture using Sweden as a reference country. Lifetime risks of hip fracture at the age of 50 years were 4.6% and 13.9% in men and women respectively, assuming all survive to current average life expectancy. Estimates increased to 8.1% and 19.5% when based on present mortality and to 11.1% and 22.7% respectively based on predicted mortality. We conclude that lifetime risks of hip fracture have been considerably underestimated.

Aged↗

Improvement of ED prediction of cardiac mortality among patients with symptoms suggestive of acute myocardial infarction.

A study was undertaken to evaluate the 1-year risk of cardiac death for patients with chest pain/suspected acute myocardial infarction in the emergency department (ED) and express the prognosis in a statistical model. Clinical variables and electrocardiogram were correlated to cardiac death during 1 year. Cox regression model was used to estimate the risk of death as a continuous function of a risk score and the time interval. From these, the prognosis for each patient can be calculated. There were 6,794 visits by 5,303 patients followed for 1 year, during which 604 patients died. The absolute risk of cardiac death can be calculated from the independent predictors for cardiac death: age; sex; histories of diabetes mellitus, hypertension, and congestive heart failure; and symptoms, electrocardiographic pattern, and degree of suspicion of acute myocardial infarction on admission. This model allows estimation of the prognosis for every patient with chest pain/suspected acute myocardial infarction from data easily available in the ED.

Adolescent↗

Early surgery in infective endocarditis.

Optimal timing of surgical intervention in infective endocarditis is important in reducing mortality. We prospectively studied 126 consecutive episodes of infective endocarditis treated in one institution over 5 years, with special emphasis on long-term results and on the effects on outcome of surgical interventions. Twenty-six patients (21%) underwent acute surgery on median treatment day 14. Mortality during treatment was 8% for patients undergoing acute surgery vs. 11% for those not undergoing surgery, and the adjusted 5-year survival rate of acute surgically treated patients was 91%, compared with 69% for the medically treated patients. Using univariate analysis, excess mortality during 5 years follow-up was associated with new cardiac decompensation at entry (p < 0.01), age (p < 0.01), no acute surgery (p < 0.05) and mitral valve involvement (p < 0.05). Multivariate analysis showed new cardiac decompensation at entry to be an independent predictor of cardiac death at 5 years follow-up (relative risk 2.39; CI 1.05-5.45), while no surgery during active disease implied a relative risk of 3.45, though not statistically significant. Patients undergoing surgery very early (< or = 10 days of treatment) did not have a poorer outcome. Acute valve replacement, as compared with medical therapy only, might be important to increase both short-term and long-term survival in infective endocarditis.

Acute Disease↗

Factors affecting results after flexor tendon repair in zone II: a multivariate prospective analysis.

A stepwise multiple regression procedure was used to examine the influence of 12 to 13 independent variables on five outcome variables, 1 year after flexor tendon repair in zone II, in a consecutive series of 135 patients treated with early controlled motion. Of the included variables, controlled interphalangeal joint range of motion 3 weeks postoperatively was the single most influential factor with regard to final active interphalangeal joint range of motion. Together with age, swelling, the number of digits, and the number of tendons injured, it accounted for 18% to 19% of the total variance in active range of motion; 14% to 15% of the variance in extension deficits and 41% of the variance in grip strength could be accounted for by variables included in the study. A large part of the variance in all the outcome variables was probably related to the psychological and biologic characteristics of the patient.

Adolescent↗

Long-term follow-up of patients with untreated scoliosis. A study of mortality, causes of death, and symptoms.

The mortality and causes of death in 115 patients (80 women), born 1902-1937, with untreated scoliosis were compared to the expected according to official Swedish statistics. Subgrouping for cause and onset of scoliosis was done. Fifty-five patients had died; 21 of respiratory failure and 17 of cardiovascular diseases. The mortality was significantly (P less than 0.001) increased. The increased risk was apparent at 40-50 years of age. The mortality was significantly increased in infantile (P less than 0.001) and juvenile (P less than 0.01) scoliosis but not in adolescent scoliosis. The mortality was also increased in post-polio scoliosis, scoliosis combined with rickets and scoliosis of unknown etiology indicating an increased mortality in idiopathic scoliosis. Among the surviving patients anti-hypertensive treatment was frequent (23 of 50).

Adolescent↗