Trunk Muscle Composition 2 Months After Hip Fracture: Findings From the Baltimore Hip Studies.

OBJECTIVE: To determine if hip fracture patients would have smaller cross-sectional area (CSA) and lower radiological attenuation (suggesting greater fat infiltration) in all trunk muscles as compared to older adults without hip fractures. DESIGN: Cross-sectional analysis of computed tomography (CT) scans. SETTING: Clinical imaging facility. PARTICIPANTS: Forty-one white participants (19 men, 22 women) from the Baltimore Hip Studies seventh cohort at 2 months postfracture were compared to 693 white participants (424 men, 269 women) from the Health, Aging and Body Composition (Health ABC) study at the year 6 visit (N=734). INTERVENTION: Not applicable. MAIN OUTCOME MEASURES: Trunk muscle CSA and attenuation values were obtained from a single 10-mm, axial CT scan completed at the L4-L5 disc space in each participant. RESULTS: The hip fracture cohort had significantly smaller CSA for all trunk muscles (range: 12.1%-38% smaller) compared to the Health ABC cohort (P<.01), with the exception of the rectus abdominus muscle in men (P=.12). But, hip fracture patients, particularly female patients, had higher attenuation levels (lower intramuscular fat) in all trunk muscles (P<.0001). CONCLUSIONS: Findings are consistent with atrophy of the trunk muscles in the hip fracture population without a high level of intramuscular fat. Future work should evaluate the role of trunk muscle composition in the functional recovery of older adults after hip fracture.

Residual Disability, Mortality, and Nursing Home Placement After Hip Fracture Over 2 Decades.

OBJECTIVE: To examine trends in 12-month postfracture residual disability, nursing home placement, and mortality among patients with a hip fracture between 1990 and 2011. DESIGN: Secondary analysis of 12-month outcomes from 3 cohort studies and control arms of 2 randomized controlled trials. SETTING: Original studies were conducted as part of the Baltimore Hip Studies (BHS). PARTICIPANTS: Community-dwelling patients ≥65 years of age hospitalized for surgical repair of a nonpathologic hip fracture (N=988). MAIN OUTCOME MEASURES: Twelve-month residual disability, mortality, and nursing home residency were examined in case-mix adjusted models by sex and study. Residual disability was calculated by subtracting prefracture scores of Lower Extremity Physical Activities of Daily Living from scores at 12 months postfracture. We also examined the proportion of individuals with a 12-month score higher than their prefracture score (residual disability>0). RESULTS: Only small improvements were seen in residual disability between 1990 and 2011. No significant differences were seen for men between BHS2 (enrollment 1990-1991; mean residual disability=3.1 activities; 95% confidence interval [CI], 2.16-4.10) and BHS7 (enrollment 2006-2011; mean=3.1 activities; 95% CI, 2.41-3.82). In women, residual disability significantly improved from BHS2 (mean=3.5 activities; 95% CI, 2.95-3.99) to BHS3 (enrollment 1992-1995; mean=2.7 activities; 95% CI, 2.01-3.30) with no significant improvements in later studies. After adjustment, a substantial proportion (91% of men and 79% of women) had a negative outcome (residual disability, died, or nursing home residence at 12 months) in the most recently completed study (BHS7). CONCLUSIONS: Over 2 decades, patients undergoing usual care post-hip fracture still had substantial residual disability. Additional clinical and research efforts are needed to determine how to improve hip fracture treatment, rehabilitation, and subsequent outcomes.

Association between pre-hip fracture depression and days at home after fracture and assessing sex differences.

BACKGROUND: Hip fracture and depression are important public health issues among older adults, but how pre-fracture depression impacts recovery after hip fracture is unknown, especially among males who often experience greater depression severity. Days at home (DAH), or the days spent outside a hospital or healthcare facility, is a novel, patient-centered outcome that can capture meaningful aspects of fracture recovery. How pre-fracture depression impacts DAH after fracture, and related sex differences, remains unclear. METHODS: Participants included 63,618 Medicare fee-for-service beneficiaries aged 65+ years, with a hospitalization claim for hip fracture surgery between 2010 and 2017. The primary exposure was a diagnosis of depression at hospital admission, and the primary outcome was total DAH over 12 months post-discharge. Longitudinal associations between pre-fracture depression and the count of DAH among beneficiaries were estimated using Poisson regression models after adjustment for covariates; sex-by-depression interactions were also assessed. Incidence rate ratios (IRRs) and 95% confidence intervals (CIs) reflecting relative differences were estimated from these models. RESULTS: Overall, beneficiaries with depression were younger, White females, and spent 11 fewer average DAH compared to counterparts without depression when demographic factors (age and sex) (IRR = 0.91; 95% CI = 0.90, 0.92; p < 0.0001) and social determinants of health (race, Medicaid dual eligibility, and poverty) were adjusted for (IRR = 0.92; 95% CI = 0.91, 0.93; p < 0.0001), but this association attenuated after adjusting for medical complexities (IRR = 0.99; 95% CI = 0.98, 1.01; p = 0.41) and facility and geographical factors (IRR = 1.0037; 95% CI = 0.99, 1.02; p = 0.66). There was no evidence of effect modification by sex. CONCLUSIONS: The comorbidity burden of preexisting depression may impact DAH among both male and female Medicare beneficiaries with hip fracture. Results suggest a holistic health approach and secondary prevention of depressive symptoms after hip fracture.

Associations of sex, Alzheimer's disease and related dementias, and days alive and at home among older Medicare beneficiaries recovering from hip fracture.

BACKGROUND: Males constitute 25% of older adults who experience hip fractures in the United States; a concerning upward trend given poorer health and outcomes among male survivors. Male sex is associated with worse cognitive performance after hip fracture, impacting participation in rehabilitation and long-term outcomes especially for those with Alzheimer's disease or related dementias (ADRD). However, little research has evaluated whether sex differences in post-fracture recovery are greater among those living with ADRD. METHODS: Data were drawn from 2010 to 2017 Medicare fee-for-service beneficiaries aged 65 years and older who survived hospitalization for hip fracture (n = 69,581). The primary outcome was days alive and at home (DAAH), a validated patient-centered claims-based outcome calculated as 365 days from fracture minus days in hospital, nursing home, rehabilitation facility, emergency department, or time after death. Multivariable Poisson regressions with an interaction term between sex and ADRD status were to model the association between DAAH and ADRD in the 12 months post hip fracture, adjusting for demographics, injury severity, chronic disease burden, and hospital-level fixed effects. RESULTS: Compared to females, males were younger and had more comorbidities at the time of fracture. Among survivors, males with ADRD spent a mean of 160.7 DAAH compared to 228.4 for males without ADRD, 177.8 for females with ADRD, and 248.0 for females without ADRD. In adjusted analyses, males without ADRD spent 8.2% fewer DAAH compared to females (rate ratio [RR] = 0.92, 95% CI 0.92-0.92). This relative sex difference increased significantly when comparing those living with ADRD, with males spending an additional 3.3% fewer DAAH (interaction RR = 0.96, 95% CI 0.96-0.97). CONCLUSIONS: Males spend fewer DAAH after hip fracture than females, and this difference increases modestly for males living with ADRD compared to females. This suggests that cognitive impairment may be a small but significant contributor to sex-based differences observed during hip fracture recovery.

Predictors of mobility status one year post hip fracture among community-dwelling older adults prior to fracture: A prospective cohort study.

BACKGROUND: Orthopedists and other clinicians assess recovery potential of hip fracture patients at 2 months post-fracture for care planning. It is unclear if examining physical performance (e.g., balance, gait speed, chair stand) during this follow-up visit can identify individuals at a risk of poor functional recovery, especially mobility, beyond available information from medical records and self-report. METHODS: Data came from 162 patients with hip fracture enrolled in the Baltimore Hip Studies-7th cohort. Predictors of mobility status (ability to walk 1 block at 12 months post-fracture) were the Short Physical Performance Battery (SPPB) comprising balance, walking and chair rise tasks at 2 months; baseline medical chart information (sex, age, American Society of Anesthesiologist physical status rating, type of fracture and surgery, and comorbidities); and self-reported information about the physical function (ability to walk 10 feet and 1 block at pre-fracture and at 2 months post-fracture). Prediction models of 12-month mobility status were built using two methods: (1) logistic regression with least absolute shrinkage and selection operator (LASSO) regularization, and (2) classification and regression trees (CART). Area under ROC curves (AUROC) assessed discrimination. RESULTS: The participants had a median age of 82 years, and 49.3% (n = 80) were men. Two-month SPPB and gait speed were selected as predictors of 12-month mobility by both methods. Compared with an analytic model with medical chart and self-reported information, the model that additionally included physical performance measures had significantly better discrimination for 12-month mobility (AUROC 0.82 vs. 0.88, p = 0.004). CONCLUSION: Assessing SPPB and gait speed at 2 months after a hip fracture in addition to information from medical records and self-report significantly improves prediction of 12-month mobility. This finding has important implications in providing tailored clinical care to patients at a greater risk of being functionally dependent who would not otherwise be identified using regularly measured clinical markers.

Thigh Muscle Composition and Its Relationship to Functional Recovery Post Hip Fracture Over Time and Between Sexes.

BACKGROUND: Computed tomography (CT)-scan measures of muscle composition may be associated with recovery post hip fracture. METHODS: In an ancillary study to Baltimore Hip Studies Seventh cohort, older adults were evaluated at 2 and 6 months post hip fracture. CT-scan measures of muscle were acquired at 2 months. Short Physical Performance Battery (SPPB) was measured at 2 and 6 months. Generalized estimating equations were used to model the association of muscle measures and physical function, adjusting for age, sex, body mass index, and time postfracture. RESULTS: Seventy-one older adults (52% males, age 79.6 ± 7.3 years) were included. At 2-months, males had greater thigh cross-sectional area (CSA, p < .0001) and less low-density muscle (p = .047), and intermuscular adipose tissue (p = .007) than females on the side of the fracture, while females performed better on the SPPB (p = .05). Muscle measures on the fractured side were associated with function at 2 months in both sexes. Participants with the lowest tertile of muscle CSA difference at 2-months, indicating greater symmetry in CSA between limbs, performed better than the other 2 tertiles at 6-months. Males performed worse in functional measures at baseline and did not recover as well as females (p = .02). CONCLUSION: CT-scan measures of muscle CSA and fatty infiltration were associated with function at 2-months post hip fracture and with improvement in function by 6 months. Observed sex differences in these associations suggest that rehabilitation strategies may need to be adapted by sex after hip fracture.

Four Square Step Test Performance in Hip Fracture Patients.

BACKGROUND AND PURPOSE: Preventing subsequent falls in persons recovering from hip fracture is paramount. The Four Square Step Test (FSST) is a fast, easy measure of dynamic balance, with times more than 15 seconds previously associated with multiple fall risk in older adults. This study investigates among hip fracture patients (1) FSST performance, and how (2) unique population characteristics (such as fracture side) and (3) cognition impact FSST performance. METHODS: Patients with hip fracture (n = 40) 60 years and older came from an ancillary study to a larger randomized controlled trial testing two 16-week in-home physical therapy interventions after completion of usual care rehabilitation. Baseline measurers included: FSST, demographics, fracture characteristics, Modified Mini-Mental State Examination (3MS), Hooper Visual Organization Test (HVOT), and Trails Making Tests (TMT) A and B. RESULTS: Of 40 patients with hip fracture, 13 did not complete the FSST at baseline and were significantly older (P = .040) and performed worse on cognitive tests (3MS, HVOT, TMT-B; P < .05). Mean FSST time was 24.3 ± 13.1 seconds for the other 27, of whom 7 finished in less than 15 seconds. A significant 3-way interaction was observed, such that those with left-side pertrochanteric fractures who performed poorly on the HVOT did significantly worse on the FSST (P < .01, R2 = 0.93). DISCUSSION: Almost one-third of patients with hip fracture could not perform the FSST after completing usual care rehabilitation. Inability to perform the FSST was not random, as those without the FSST were physically and cognitively worse than those who did perform the FSST. Among those who could attempt the FSST, few performed well. Cognitive ability related to spatial orientation and fracture characteristics such as fracture side and fracture type has a synergistic effect on FSST performance. CONCLUSIONS: This is one of the first studies to assess the FSST in a population with hip fracture. At 4 months after hip fracture, most patients cannot perform the FSST in less than 15 seconds. Fracture side and fracture type appear important to FSST performance, as does cognition. More work needs to be done longitudinally to study the FSST in patients with hip fracture.

Long-term sex differences in all-cause and infection-specific mortality post hip fracture.

BACKGROUND: Mortality rates among men are double that of women in the first 2 years after hip fracture and may be related to more infections. Research has only examined differences in short-term mortality after hip fracture. Thus, the objective was to determine if long-term all-cause mortality and infection-specific mortality rates are higher in men compared to women. METHODS: Data come from a prospective cohort study (Baltimore Hip Studies 7th [BHS-7]) with up to 10.2 years of follow-up (2006-2018). The participants were selected from eight acute care hospitals in the 25-hospital BHS network. Enrolled women were frequency-matched (1:1) to men on timing of admission for hip fracture that yielded an analytic sample size of 300 participants (155 women, 145 men). Associations between sex and mortality were analyzed using Cox proportional hazard models and cause-specific Cox models adjusted for age, cognition, body mass index, pre-fracture lower extremity activities of daily living limitation, depressive symptoms, and comorbidity. RESULTS: Participants had a mean age of 80 years, 48% (n = 145) were men and the median follow-up was 4.9 (interquartile range = 2.3-8.7) years. Over the follow-up period after hospital admission for hip fracture, 237 (79.0%) participants died of all causes (132 men and 105 women) and 38 (12.7%) died of infection-specific causes (25 men and 13 women). Men had significantly higher rates of all-cause mortality [hazard ratio (HR) = 2.31(95% confidence interval [CI] 2.02-2.59)] and infection-specific mortality (HR = 4.43, CI 2.07-9.51) compared to women. CONCLUSIONS: Men had a two-fold higher rate of all-cause mortality and four-fold higher rate of infection-specific mortality compared to women over a follow-up period of up to 10.2 years. Findings suggest that interventions to prevent and treat infections, tailored by sex, may be needed to narrow significant differences in long-term mortality rates between men and women after hip fracture.

Differential misclassification of cognitive impairment by sex among hip fracture patients.

BACKGROUND: Males have worse outcomes after hip fracture than female counterparts. Cognitive impairment (CI) also increases the risk of poor recovery from hip fracture; however, CI is under-recognized. Patient sex may contribute to this under-recognition through differential misclassification. The objective of this study was to measure under-recognition and differential misclassification of CI by patient sex. METHODS: A cross-sectional analysis of baseline data from an observational cohort study of community-dwelling hip fracture patients aged 65 and older (n = 339; females = 171, males = 168) recruited from eight hospitals in the greater Baltimore, MD area within 15 days of hospitalization for surgical repair with cognitive testing within 22 days of admission. Indication of Alzheimer's disease or related dementias and/or delirium as a postoperative complication in the medical record was considered evidence of documented CI. Observed CI was measured with the Modified Mini-Mental State Examination (3MS, ≤78). Source of cognitive impairment identification (SCI) was defined as: "3MS Only," "Hospital Record Only," "Both," "No CI" was compared between males and females using logistic regression. RESULTS: Males had more comorbidities and worse physical status upon admission, but otherwise had similar hospital experiences. SCI distribution was 12.7% "3MS Only" (n = 42), 11.5% "Hospital Record Only" (n = 38), 9.4% "Both" (n = 31), and "No CI" (n = 219). Males were more likely to be identified with CI using the "3MS Only" and "Both," and females were more likely to have no indication of CI. CONCLUSION: There were sex differences in the documentation of CI versus observed impairment. Males had more CI using direct testing. This may be contributing to sex differences in recovery outcomes after hip fracture. Results support the implementation of cognitive testing in hip fracture patients to reduce the impact of differential misclassification by patient sex.

Sex Differences in Recovery Across Multiple Domains Among Older Adults With Hip Fracture.

BACKGROUND: Hip fractures are a public health problem among older adults, but most research on recovery after hip fracture has been limited to females. With growing numbers of hip fractures among males, it is important to determine how recovery outcomes may differ between the sexes. METHODS: 168 males and 171 females were enrolled within 15 days of hospitalization with follow-up visits at 2, 6, and 12 months postadmission to assess changes in disability, physical performance, cognition, depressive symptoms, body composition, and strength, and all-cause mortality. Generalized estimating equations examined whether males and females followed identical outcome recovery assessed by the change in each outcome. RESULTS: The mean age at fracture was similar for males (80.4) and females (81.4), and males had more comorbidities (2.5 vs 1.6) than females. Males were significantly more likely to die over 12 months (hazard ratio 2.89, 95% confidence interval: 1.56-5.34). Changes in outcomes were significantly different between males and females for disability, gait speed, and depressive symptoms (p < .05). Both sexes improved from baseline to 6 months for these measures, but only males continued to improve between 6 and 12 months. There were baseline differences for most body composition measures and strength; however, there were no significant differences in change by sex. CONCLUSIONS: Findings confirm that males have higher mortality but suggest that male survivors have continued functional recovery over the 12 months compared to females. Research is needed to determine the underlying causes of these sex differences for developing future prognostic information and rehabilitative interventions.

Change in vertebral strength and bone mineral density in men and women over the year post-hip fracture: a subgroup analysis.

This study examines changes in bone density and strength in the spine over the year after hip fracture to see if there are differences in the changes between men and women. Results show losses in the spine that may increase the risk of subsequent vertebral fractures, particularly for women. PURPOSE: Compare changes over the first year post-hip fracture in vertebral bone mineral density (BMD) and compressive strength, measured from quantitative computed tomography (QCT) scans of the spine (T12-L1), between women and men. METHODS: QCT scans were performed on 37 participants (21 men and 16 women) at 2 and 12 months post-hip fracture as part of an ancillary observational study of hip fracture recovery in older community-dwelling men and women. Vertebral BMD and compressive strength were calculated using VirtuOst® (O.N. Diagnostics, Berkeley, CA). Unpaired t-tests were used to compare men and women with respect to baseline demographics, measurements of BMD and bone strength for the whole vertebra and the cortical and trabecular compartments, and any changes in these parameters between months 2 and 12. RESULTS: At 2 months post-fracture, there were no significant sex differences in any measurements of vertebral strength or BMD. Between months 2 and 12, vertebral strength decreased significantly in women (- 3.8%, p < 0.05) but not in men (- 2.3%, p < 0.20), vertebral trabecular BMD decreased similarly in both sexes (- 5.7% women; - 6.0% men), but cortical BMD did not change for either sex. CONCLUSION: Despite the small sample size, these findings suggest that appreciable loss of vertebral trabecular bone can occur for both sexes in the year following hip fracture, which may increase the risk of subsequent vertebral fracture, particularly for women.

Using Treatment Fidelity Measures to Understand Walking Recovery: A Secondary Analysis From the Community Ambulation Project.

OBJECTIVES: Physical therapist intervention studies can be deemed ineffective when, in fact, they may not have been delivered as intended. Measurement of treatment fidelity (TF) can address this issue. The purpose of this study was to describe TF of a home-based intervention, identify factors associated with TF, and examine whether components of TF were associated with the outcome of change in 6-minute walk distance (∆6MWD). METHODS: This is a secondary analysis of community-dwelling hip fracture participants who completed standard therapy and were randomly assigned to the active intervention (Push). Push was 16 weeks of lower extremity strengthening, function, and endurance training. TF was defined as delivery (attendance rate, exercise duration) and receipt (progression in training load, heart rate reserve [HRR] during endurance training, and exercise position [exercise on floor]). The outcome was ∆6MWD. Independent variables included baseline (demographic and clinical) measures. Descriptive statistics were calculated; linear and logistic regressions were performed. RESULTS: Eighty-nine participants were included in this analysis; 59 (66%) had attendance of 75% or greater. Participants walked for 20 minutes or more for 78% of sessions. The average training load increased by 22%; the mean HRR was 35%; and 61 (69%) participants exercised on the floor for at least 75% of sessions. Regression analyses showed that a higher body mass index and greater baseline 6MWD were related to components of TF; 4 out of 5 components of TF were significantly related to ∆6MWD. The strongest TF relationship showed that those who exercised on the floor improved by 62 m (95% CI = 31-93 m) more than those who did not get on the floor. CONCLUSIONS: Measures of TF should extend beyond attendance rate. This analysis demonstrates how measures of TF, including program attendance, progression in training load, endurance duration, and exercising on the floor were significantly related to improvement in 6MWD in participants post hip fracture. IMPACT: This careful analysis of treatment fidelity assured that the intervention was delivered and received as intended. Analysis of data from a large trial with participants after hip fracture showed that regular attendance, frequent endurance training for 20 minutes, increases in lower extremity training loads, and exercising on the floor were associated with improvements in the outcome of 6-minute-walk distance. The strongest association with improvement was exercising on the floor.

Application of SDOC Cut Points for Low Muscle Strength for Recovery of Walking Speed After Hip Fracture.

BACKGROUND: Sarcopenia is often conceptualized as a precursor to loss of mobility, but its effect on recovery of mobility after a hip fracture is unknown. We determined the prevalence of low muscle strength (weakness) after hip fracture using putative sarcopenia metrics (absolute grip strength, and grip strength normalized to body mass index, total body fat, arm lean mass, and weight) identified by the Sarcopenia Definitions and Outcomes Consortium (SDOC). METHODS: We examined two well-characterized hip fracture cohorts of community-dwelling older adults from the Baltimore Hip Studies (BHS). The prevalence of muscle weakness was assessed using the SDOC cut points compared to published definitions at 2 and 6 months postfracture. We assessed associations of 2-month weakness with 6-month walking speed <0.6 m/s and calculated the sensitivity and specificity in predicting lack of meaningful change in walking speed (change < 0.1 m/s) at 6 months. RESULTS: Two hundred and forty-six participants (192 women; 54 men) were included; mean (SD) age of 81 (8) for women and 78 (7) for men. At 2 months, 91% women and 78% men exhibited slow walking speed (< 0.6 m/s). SDOC grip strength standardized by weight (<0.34 kg women, <0.45 kg men) was the most prevalent measure of weakness in men (74%) and women (79%) and provided high sensitivity in men (86%) and women (84%) predicting lack of meaningful change in walking speed at 6 months, although specificity was poor to moderate. CONCLUSIONS: SDOC cut points for grip strength standardized to weight provided consistent indication of poor walking speed performance post-hip fracture.

Hip fracture and its consequences: differences between men and women.

This article describes the state of knowledge regarding gender differences with respect to hip fracture and its subsequent outcomes. Most of the work to date investigating hip fracture patients has been done with women, yet some evidence from a few studies with a significant number of male hip fracture patients and from nonfracture samples suggests that women and men may be different at the time of fracture and will have a different course of recovery.

Bone mineral density, soft tissue body composition, strength, and functioning after hip fracture.

BACKGROUND: Although substantial decrements in bone, muscle, and functional ability have been reported to follow the occurrence of hip fracture in elderly women, little is known about the interrelation of these consequences. The authors evaluated the associations among physiologic and functional factors during recovery from hip fracture to determine whether any consistent sequence of events followed and whether markers of functional outcomes could be identified. METHODS: Two hundred five community-dwelling women aged 65 years and older who sustained hip fracture between 1992 and 1995 and were admitted to one of two acute care hospitals in metropolitan Baltimore, Maryland, participated in a 1-year prospective cohort study. Bone mineral density, lean mass, and fat mass were measured by dual-energy X-ray absorptiometry during the hospitalization and 2, 6, and 12 months later. Functional limitations were self-reported and grip strength was measured during interviews at the same time points. Correlation coefficients were calculated for all possible pairs of measures and time points. RESULTS: Losses of femoral neck bone mineral density and lean body mass and gains in fat mass were observed. Grip strength showed early improvement but declined by 1 year to levels close to those seen during hospitalization. Functional outcomes showed minimal correlation with bone or body composition and only moderate correlation with strength. CONCLUSIONS: Physiologic and functional declines follow hip fracture in elderly women. These are largely independent of one another and suggest that interventions to maximize recovery must simultaneously target multiple areas, including bone, muscle, strength, and function.

Asymmetry in CT Scan Measures of Thigh Muscle 2 Months After Hip Fracture: The Baltimore Hip Studies.

BACKGROUND: Hip fracture is an important problem for older adults with significant functional consequences. After hip fracture, reduced muscle loading can result in muscle atrophy. METHODS: We compared thigh muscle characteristics in the fractured leg to those in the nonfractured leg in participants from the Baltimore Hip Studies 7th cohort using computed tomography scan imaging. RESULTS: At 2 months postfracture, a single 10mm axial computed tomography scan was obtained at the midthigh level in 43 participants (23 men, 20 women) with a mean age of 79.9 years (range: 65-96 years), and thigh muscle cross-sectional area, cross-sectional area of intermuscular adipose tissue, and mean radiologic attenuation were measured. Total thigh muscle cross-sectional area was less on the side of the fracture by 9.46cm(2) (95% CI: 5.97cm(2), 12.95cm(2)) while the cross-sectional area of intermuscular adipose tissue was greater by 2.97cm(2) (95% CI: 1.94cm(2), 4.01cm(2)) on the fractured side. Mean muscle attenuation was lower on the side of the fracture by 3.66 Hounsfield Units (95% CI: 2.98 Hounsfield Units, 4.34 Hounsfield Units). CONCLUSIONS: The observed asymmetry is consistent with the effect of disuse and inflammation in the affected limb along with training effects in the unaffected limb due to the favoring of this leg with ambulation during the postfracture period.

Asymmetry in CT Scan Measures of Thigh Muscle 2 Months After Hip Fracture: The Baltimore Hip Studies.

BACKGROUND: Hip fracture is an important problem for older adults with significant functional consequences. After hip fracture, reduced muscle loading can result in muscle atrophy. METHODS: We compared thigh muscle characteristics in the fractured leg with those in the nonfractured leg in participants from the Baltimore Hip Studies 7th cohort using computed tomography (CT) scan imaging. RESULTS: At 2 months postfracture, a single 10-mm axial CT scan was obtained at the midthigh level in 47 participants (26 men and 21 women) with a mean age of 80.4 years (range 65-96), and thigh muscle cross-sectional area (CSA), CSA of intermuscular adipose tissue (IMAT), as well as mean radiological attenuation were measured. Total thigh muscle CSA was less on the side of the fracture by 9.2 cm(2) (95% CI: 5.9, 12.4 cm(2)), whereas the CSA of IMAT was greater by 2.8 cm(2) (95% CI: 1.9, 3.8 cm(2)) on the fractured side. Mean muscle attenuation was lower on the side of the fracture by 3.61 HU (95% CI: 2.99, 4.24 HU). CONCLUSIONS: The observed asymmetry is consistent with the effect of disuse and inflammation in the affected limb along with training effects in the unaffected limb due to the favoring of this leg with ambulation during the postfracture period.

Gender differences in mortality after hip fracture: the role of infection.

UNLABELLED: Possible explanations for the observed gender difference in mortality after hip fracture were examined in a cohort of 804 men and women. Mortality during 2 years after fracture was identified from death certificates. Men were twice as likely as women to die, and deaths caused by pneumonia/influenza and septicemia showed the greatest increase. INTRODUCTION: Men are more likely to die after hip fracture than women. Gender differences in predisposing factors and causes of death have not been systematically studied. MATERIALS AND METHODS: Participants (173 men and 631 women) in the Baltimore Hip Studies cohort enrolled in 1990 and 1991, at the time of hospitalization for hip fracture, were followed longitudinally for 2 years. Cause-specific mortality 1 and 2 years after hip fracture, identified from death certificates, was compared by gender and to population rates. RESULTS AND CONCLUSIONS: Men were twice as likely as women to die during the first and second years after hip fracture (odds ratio [OR], 2.28; 95% CI, 1.47, 3.54 and OR, 2.21; 95% CI, 1.48, 3.31). Prefracture medical comorbidity, type of fracture, type of surgical procedure, and postoperative complications did not explain the observed difference. Greatest increases in mortality, relative to the general population, were seen for septicemia (relative risk [RR], 87.9; 95% CI, 16.5, 175 at 1 year and RR, 32.0; 95% CI, 7.99, 127 at 2 years) and pneumonia (RR, 23.8; 95% CI, 12.8, 44.2 at 1 year and RR, 10.4; 95% CI, 3.35, 32.2 at 2 years). The magnitude of increase in deaths caused by infection was greater for men than for women in both years. Mortality rates for men and women were similar if deaths caused by infection were excluded (3.46 [1.79, 6.67] and 2.47 [1.63, 3.72] at 1 year and 0.96 [0.48, 1.91] and 1.26 [0.80, 1.98] at 2 years). Deaths related to infections (pneumonia, influenza, and septicemia) seem to be largely responsible for the observed gender difference. In conclusion, an increased rate of death from infection and a gender difference in rates persists for at least 2 years after the fracture.

Body mass index is positively associated with bone mineral density in US older adults.

UNLABELLED: Literature has been conflicting as to whether obesity is protective against osteoporosis. Understanding the relationship is particularly important in light of the increasing prevalence of obesity among older adults. Study results confirm a protective association between obesity and osteoporosis in a recent, nationally representative sample of US older adults. PURPOSE: Currently, the majority of US older adults are either overweight or obese. Evidence regarding the relationship between body composition measures and bone mass is conflicting, possibly because different measures of obesity reflect multiple mechanisms. Additionally, there are important age, gender, and racial differences in a risk of osteoporosis and fat mass composition. The objective of this study was to examine the association between body mass index (BMI) and bone mineral density (BMD) in a recent, nationally representative sample of US older adults as well as to see if this relationship differs by age, sex, and race. METHODS: Data for this study were obtained from the National Health and Nutrition Examination Survey (2005-2008) for adults ages 50 and older (n = 3,296). Linear regression models were used to predict BMD of the femoral neck (measured by dual-energy X-ray absorptiometry (DXA)) as a function of BMI (measured height and weight) and a range of study covariates. RESULTS: Every unit increase in BMI was associated with an increase of 0.0082 g/cm(2) in BMD (p < 0.001). Interaction terms for BMI and age (p = 0.345), BMI and sex (p = 0.413), and BMI and race (p = 0.725) were not statistically significant. CONCLUSIONS: Study results confirm the positive association between BMI and BMD, and this relationship does not differ by age, sex, or race. A 10-unit increase in BMI (e.g., from normal BMI to obese) would result in moving an individual from an osteoporotic BMD level to a normal BMD level. Results demonstrate a protective, cross-sectional association between obesity and osteoporosis in a recent sample of US older adults.