Comparison of the Test-negative Design and Cohort Design With Explicit Target Trial Emulation for Evaluating COVID-19 Vaccine Effectiveness

BACKGROUND

Observational studies are used for estimating vaccine effectiveness under real-world conditions. The practical performance of two common approaches-cohort and test-negative designs-need to be compared for COVID-19 vaccines.

METHODS

We compared the cohort and test-negative designs to estimate the effectiveness of the BNT162b2 vaccine against COVID-19 outcomes using nationwide data from the United States Department of Veterans Affairs. Specifically, we (1) explicitly emulated a target trial using follow-up data and evaluated the potential for confounding using negative controls and benchmarking to a randomized trial, (2) performed case-control sampling of the cohort to confirm empirically that the same estimate is obtained, (3) further restricted the sampling to person-days with a test, and (4) implemented additional features of a test-negative design. We also compared their performance in limited datasets.

RESULTS

Estimated BNT162b2 vaccine effectiveness was similar under all four designs. Empirical results suggested limited residual confounding by healthcare-seeking behavior. Analyses in limited datasets showed evidence of residual confounding, with estimates biased downward in the cohort design and upward in the test-negative design.

CONCLUSION

Vaccine effectiveness estimates under a cohort design with explicit target trial emulation and a test-negative design were similar when using rich information from the VA healthcare system, but diverged in opposite directions when using a limited dataset. In settings like ours with sufficient information on confounders and other key variables, the cohort design with explicit target trial emulation may be preferable as a principled approach that allows estimation of absolute risks and facilitates interpretation of effect estimates.

Statins, Mortality, and Major Adverse Cardiovascular Events Among US Veterans With Chronic Kidney Disease

Importance

There are limited data for the utility of statins for primary prevention of atherosclerotic cardiovascular disease (ASCVD) and death in adults with chronic kidney disease (CKD).

Objective

To evaluate the association of statin use with all-cause mortality and major adverse cardiovascular events (MACE) among US veterans older than 65 years with CKD stages 3 to 4.

Design, Setting, and Participants

This cohort study used a target trial emulation design for statin initiation among veterans with moderate CKD (stages 3 or 4) using nested trials with a propensity weighting approach. Linked Veterans Affairs (VA) Healthcare System, Medicare, and Medicaid data were used. This study considered veterans newly diagnosed with moderate CKD between 2005 and 2015 in the VA, with follow-up through December 31, 2017. Veterans were older than 65 years, within 5 years of CKD diagnosis, had no prior ASCVD or statin use, and had at least 1 clinical visit in the year prior to trial baseline. Eligibility criteria were assessed for each nested trial, and Cox proportional hazards models with bootstrapping were run. Analysis was conducted from July 2021 to October 2023.

Exposure

Statin initiation vs none.

Main Outcomes and Measures

Primary outcome was all-cause mortality; secondary outcome was time to first MACE (myocardial infarction, transient ischemic attack, stroke, revascularization, or mortality).

Results

Included in the analysis were 14 828 veterans. Mean (SD) age at CKD diagnosis was 76.9 (8.2) years, 14 616 (99%) were men, 10 539 (72%) White, and 2568 (17%) Black. After expanding to person-trials and assessing eligibility at each baseline, there were 151 243 person-trials (14 685 individuals) of nonstatin initiators and 2924 person-trials (2924 individuals) of statin initiators included. Propensity score adjustment via overlap weighting with nonparametric bootstrapping resulted in covariate balance, with mean (SD) follow-up of 3.6 (2.7) years. The hazard ratio for all-cause mortality was 0.91 (95% CI, 0.85-0.97) comparing statin initiators to noninitiators. The hazard ratio for MACE was 0.96 (95% CI, 0.91-1.02). Results remained consistent in prespecified subgroup analyses.

Conclusions and Relevance

In this target trial emulation of statin initiation in US veterans older than 65 years with CKD stages 3 to 4 and no prior ASCVD, statin initiation was significantly associated with a lower risk of all-cause mortality but not MACE. Results should be confirmed in a randomized clinical trial.

Comparative effectiveness of third doses of mRNA-based COVID-19 vaccines in US veterans

Vaccination against SARS-CoV-2 has been effective in reducing the burden of severe disease and death from COVID-19. Third doses of mRNA-based vaccines have provided a way to address waning immunity and broaden protection against emerging SARS-CoV-2 variants. However, their comparative effectiveness for a range of COVID-19 outcomes across diverse populations is unknown. We emulated a target trial using electronic health records of US veterans who received a third dose of either BNT162b2 or mRNA-1273 vaccines between 20 October 2021 and 8 February 2022, during a period that included Delta- and Omicron-variant waves. Eligible veterans had previously completed an mRNA vaccine primary series. We matched recipients of each vaccine in a 1:1 ratio according to recorded risk factors. Each vaccine group included 65,196 persons. The excess number of events over 16 weeks per 10,000 persons for BNT162b2 compared with mRNA-1273 was 45.4 (95% CI: 19.4, 84.7) for documented infection, 3.7 (2.2, 14.1) for symptomatic COVID-19, 10.6 (5.1, 19.7) for COVID-19 hospitalization, 2.0 (-3.1, 6.3) for COVID-19 intensive care unit admission and 0.2 (-2.2, 4.0) for COVID-19 death. After emulating a second target trial of veterans who received a third dose between 1 January and 1 March 2022, during a period restricted to Omicron-variant predominance, the excess number of events over 9 weeks per 10,000 persons for BNT162b2 compared with mRNA-1273 was 63.2 (95% CI: 15.2, 100.7) for documented infection. The 16-week risks of COVID-19 outcomes were low after a third dose of mRNA-1273 or BNT162b2, although risks were lower with mRNA-1273 than with BNT162b2, particularly for documented infection.

Visualizing novel connections and genetic similarities across diseases using a network-medicine based approach

Understanding the genetic relationships between human disorders could lead to better treatment and prevention strategies, especially for individuals with multiple comorbidities. A common resource for studying genetic-disease relationships is the GWAS Catalog, a large and well curated repository of SNP-trait associations from various studies and populations. Some of these populations are contained within mega-biobanks such as the Million Veteran Program (MVP), which has enabled the genetic classification of several diseases in a large well-characterized and heterogeneous population. Here we aim to provide a network of the genetic relationships among diseases and to demonstrate the utility of quantifying the extent to which a given resource such as MVP has contributed to the discovery of such relations. We use a network-based approach to evaluate shared variants among thousands of traits in the GWAS Catalog repository. Our results indicate many more novel disease relationships that did not exist in early studies and demonstrate that the network can reveal clusters of diseases mechanistically related. Finally, we show novel disease connections that emerge when MVP data is included, highlighting methodology that can be used to indicate the contributions of a given biobank.

Comparative Safety of BNT162b2 and mRNA-1273 Vaccines in a Nationwide Cohort of US Veterans

Importance

The risk of adverse events has been found to be low for participants receiving the BNT162b2 (Pfizer-BioNTech) and mRNA-1273 (Moderna Inc) vaccines in randomized trials. However, a head-to-head comparison of their safety for a broader range of potential adverse events over longer follow-up and in larger and more diverse populations is lacking, to our knowledge.

Objective

To compare the head-to-head safety in terms of risk of adverse events of the BNT162b2 and mRNA-1273 vaccines in the national health care databases of the US Department of Veterans Affairs, the largest integrated health care system in the US.

Design, Setting, and Participants

In this cohort study, the electronic health records of US veterans who received a first dose of the BNT162b2 or mRNA-1273 vaccine between January 4 and September 20, 2021, were used. Recipients of each vaccine were matched in a 1:1 ratio according to their risk factors.

Exposures

Vaccination with either the BNT162b2 vaccine, with a second dose scheduled 21 days later, or the mRNA-1273 vaccine, with a second dose scheduled 28 days later.

Main Outcomes and Measures

A large panel of potential adverse events was evaluated; the panel included neurologic events, hematologic events, hemorrhagic stroke, ischemic stroke, myocardial infarction, other thromboembolic events, myocarditis or pericarditis, arrhythmia, kidney injury, appendicitis, autoimmune events, herpes zoster or simplex, arthritis or arthropathy, and pneumonia. Risks over 38 weeks were estimated using the Kaplan-Meier estimator.

Results

Among 433 672 persons included in the matched vaccine groups, the median age was 69 years (IQR, 60-74 years), 93% of individuals were male, and 20% were Black. Estimated 38-week risks of adverse events were generally low after administration of either the BNT162b2 or the mRNA-1273 vaccine. Compared with the mRNA-1273 group, the BNT162b2 group had an excess per 10 000 persons of 10.9 events (95% CI, 1.9-17.4 events) of ischemic stroke, 14.8 events (95% CI, 7.9-21.8 events) of myocardial infarction, 11.3 events (95% CI, 3.4-17.7 events) of other thromboembolic events, and 17.1 events (95% CI, 8.8-30.2 events) of kidney injury. Estimates were largely similar among subgroups defined by age (<40, 40-69, and ≥70 years) and race (Black, White), but there were higher magnitudes of risk differences of ischemic stroke among older persons and White persons, kidney injury among older persons, and other thromboembolic events among Black persons. Small-magnitude differences between the 2 vaccines were seen within 42 days of the first dose, and few differences were seen within 14 days of the first dose.

Conclusions and Relevance

The findings of this cohort study suggest that there were few differences in risk of adverse events within 14 days of the first dose of either the BNT162b2 or the mRNA-1273 vaccine and small-magnitude differences within 42 days of the first dose. The 38-week risks of adverse events were low in both vaccine groups, although risks were lower for recipients of the mRNA-1273 vaccine than for recipients of the BNT162b2 vaccine. Although the primary analysis was designed to detect safety events unrelated to SARS-CoV-2 infection, the possibility that these differences may partially be explained by a lower effectiveness of the BNT162b2 vaccine in preventing the sequelae of SARS-CoV-2 infection compared with the mRNA-1273 vaccine could not be ruled out. These findings may help inform decision-making in future vaccination campaigns.

Impact of Coronavirus Disease 2019 (COVID-19) Severity on Long-term Events in United States Veterans Using the Veterans Affairs Severity Index for COVID-19 (VASIC)

In this retrospective cohort study of 94 595 severe acute respiratory syndrome coronavirus 2-positive cases, we developed and validated an algorithm to assess the association between coronavirus disease 2019 (COVID-19) severity and long-term complications (stroke, myocardial infarction, pulmonary embolism/deep vein thrombosis, heart failure, and mortality). COVID-19 severity was associated with a greater risk of experiencing a long-term complication 31-120 days postinfection. Most incident events occurred 31-60 days postinfection and diminished after day 91, except heart failure for severe patients and death for moderate patients, which peaked on days 91-120. Understanding the differential impact of COVID-19 severity on long-term events provides insight into possible intervention modalities and critical prevention strategies.

30-day Mortality Following COVID-19 and Influenza Hospitalization Among US Veterans Aged 65 and Older

Background

COVID‐19 and influenza are important sources of morbidity and mortality among older adults. Understanding how outcomes differ for older adults hospitalized with either infection is important for improving care. We compared outcomes from infection with COVID‐19 and influenza among hospitalized older adults.

Methods

We conducted a retrospective study of 30‐day mortality among veterans aged 65+ hospitalized with COVID‐19 from March 1, 2020–December 31, 2020 or with influenza A/B from September 1, 2017 to August 31, 2019 in Veterans Affairs Health Care System (VAHCS). COVID‐19 infection was determined by a positive PCR test and influenza by tests used in the VA system. Frailty was defined by the claims‐based Veterans Affairs Frailty Index (VA‐FI). Logistic regressions of mortality on frailty, age, and infection were adjusted for multiple confounders.

Results

A total of 15,474 veterans were admitted with COVID‐19 and 7867 with influenza. Mean (SD) ages were 76.1 (7.8) and 75.8 (8.3) years, 97.7% and 97.4% were male, and 66.9% and 76.4% were white in the COVID‐19 and influenza cohorts respectively. Crude 30‐day mortality (95% CI) was 18.9% (18.3%–19.5%) for COVID‐19 and 4.3% (3.8%–4.7%) for influenza.

Combining cohorts, the odds ratio for 30‐day mortality from COVID‐19 (versus influenza) was 6.61 (5.74–7.65). There was a statistically significant interaction between infection with COVID‐19 and frailty, but there was no significant interaction between COVID‐19 and age.

Separating cohorts, greater 30‐day mortality was significantly associated with older age (p: COVID‐19: <0.001, Influenza: <0.001) and for frail compared with robust individuals (p for trend: COVID‐19: <0.001, Influenza: <0.001).

Conclusion

Mortality from COVID‐19 exceeded that from influenza among hospitalized older adults. However, odds of mortality were higher at every level of frailty among those admitted with influenza compared to COVID‐19. Prevention will remain key to reducing mortality from viral illnesses among older adults.

The oral microbiome in relation to pancreatic cancer risk in African Americans

BACKGROUND

African Americans have the highest pancreatic cancer incidence of any racial/ethnic group in the United States. The oral microbiome was associated with pancreatic cancer risk in a recent study, but no such studies have been conducted in African Americans. Poor oral health, which can be a cause or effect of microbial populations, was associated with an increased risk of pancreatic cancer in a single study of African Americans.

METHODS

We prospectively investigated the oral microbiome in relation to pancreatic cancer risk among 122 African-American pancreatic cancer cases and 354 controls. DNA was extracted from oral wash samples for metagenomic shotgun sequencing. Alpha and beta diversity of the microbial profiles were calculated. Multivariable conditional logistic regression was used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) for associations between microbes and pancreatic cancer risk.

RESULTS

No associations were observed with alpha or beta diversity, and no individual microbial taxa were differentially abundant between cases and control, after accounting for multiple comparisons. Among never smokers, there were elevated ORs for known oral pathogens: Porphyromonas gingivalis (OR = 1.69, 95% CI: 0.80-3.56), Prevotella intermedia (OR = 1.40, 95% CI: 0.69-2.85), and Tannerella forsythia (OR = 1.36, 95% CI: 0.66-2.77).

CONCLUSIONS

Previously reported associations between oral taxa and pancreatic cancer were not present in this African-American population overall.

Comparative Effectiveness of BNT162b2 and mRNA-1273 Vaccines in U.S. Veterans

BACKGROUND

The messenger RNA (mRNA)-based vaccines BNT162b2 and mRNA-1273 are more than 90% effective against coronavirus disease 2019 (Covid-19). However, their comparative effectiveness for a range of outcomes across diverse populations is unknown.

METHODS

We emulated a target trial using the electronic health records of U.S. veterans who received a first dose of the BNT162b2 or mRNA-1273 vaccine between January 4 and May 14, 2021, during a period marked by predominance of the SARS-CoV-2 B.1.1.7 (alpha) variant. We matched recipients of each vaccine in a 1:1 ratio according to their risk factors. Outcomes included documented severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection, symptomatic Covid-19, hospitalization for Covid-19, admission to an intensive care unit (ICU) for Covid-19, and death from Covid-19. We estimated risks using the Kaplan-Meier estimator. To assess the influence of the B.1.617.2 (delta) variant, we emulated a second target trial that involved veterans vaccinated between July 1 and September 20, 2021.

RESULTS

Each vaccine group included 219,842 persons. Over 24 weeks of follow-up in a period marked by alpha-variant predominance, the estimated risk of documented infection was 5.75 events per 1000 persons (95% confidence interval [CI], 5.39 to 6.23) in the BNT162b2 group and 4.52 events per 1000 persons (95% CI, 4.17 to 4.84) in the mRNA-1273 group. The excess number of events per 1000 persons for BNT162b2 as compared with mRNA-1273 was 1.23 (95% CI, 0.72 to 1.81) for documented infection, 0.44 (95% CI, 0.25 to 0.70) for symptomatic Covid-19, 0.55 (95% CI, 0.36 to 0.83) for hospitalization for Covid-19, 0.10 (95% CI, 0.00 to 0.26) for ICU admission for Covid-19, and 0.02 (95% CI, -0.06 to 0.12) for death from Covid-19. The corresponding excess risk (BNT162b2 vs. mRNA-1273) of documented infection over 12 weeks of follow-up in a period marked by delta-variant predominance was 6.54 events per 1000 persons (95% CI, -2.58 to 11.82).

CONCLUSIONS

The 24-week risk of Covid-19 outcomes was low after vaccination with mRNA-1273 or BNT162b2, although risks were lower with mRNA-1273 than with BNT162b2. This pattern was consistent across periods marked by alpha- and delta-variant predominance. (Funded by the Department of Veterans Affairs and others.).

Pharmacoepidemiology, Machine Learning, and COVID-19: An Intent-to-Treat Analysis of Hydroxychloroquine, With or Without Azithromycin, and COVID-19 Outcomes Among Hospitalized US Veterans

Hydroxychloroquine (HCQ) was proposed as an early therapy for coronavirus disease 2019 (COVID-19) after in vitro studies indicated possible benefit. Previous in vivo observational studies have presented conflicting results, though recent randomized clinical trials have reported no benefit from HCQ amongst hospitalized COVID-19 patients. We examined the effects of HCQ alone, and in combination with azithromycin, in a hospitalized COVID-19 positive, United States (US) Veteran population using a propensity score adjusted survival analysis with imputation of missing data. From March 1, 2020 through April 30, 2020, 64,055 US Veterans were tested for COVID-19 based on Veteran Affairs Healthcare Administration electronic health record data. Of the 7,193 positive cases, 2,809 were hospitalized, and 657 individuals were prescribed HCQ within the first 48-hours of hospitalization for the treatment of COVID-19. There was no apparent benefit associated with HCQ receipt, alone or in combination with azithromycin, and an increased risk of intubation when used in combination with azithromycin [Hazard Ratio (95% Confidence Interval): 1.55 (1.07, 2.24)]. In conclusion, we assessed the effectiveness of HCQ with or without azithromycin in treating patients hospitalized with COVID-19 using a national sample of the US Veteran population. Using rigorous study design and analytic methods to reduce confounding and bias, we found no evidence of a survival benefit from the administration of HCQ.

Changes in Pain Self-Efficacy, Coping Skills, and Fear-Avoidance Beliefs in a Randomized Controlled Trial of Yoga, Physical Therapy, and Education for Chronic Low Back Pain

OBJECTIVE

We evaluated exercise interventions for cognitive appraisal of chronic low back pain (cLBP) in an underserved population.

METHODS

We conducted a secondary analysis of the Back to Health Trial, showing yoga to be noninferior to physical therapy (PT) for pain and function outcomes among adults with cLBP (n = 320) recruited from primary care clinics with predominantly low-income patients. Participants were randomized to 12 weeks of yoga, PT, or education. Cognitive appraisal was assessed with the Pain Self-Efficacy Questionnaire (PSEQ), Coping Strategies Questionnaire (CSQ), and Fear-Avoidance Beliefs Questionnaire (FABQ). Using multiple imputation and linear regression, we estimated within- and between-group changes in cognitive appraisal at 12 and 52 weeks, with baseline and the education group as references.

RESULTS

Participants (mean age = 46 years) were majority female (64%) and majority Black (57%), and 54% had an annual household income <$30,000. All three groups showed improvements in PSEQ (range 0-60) at 12 weeks (yoga, mean difference [MD] = 7.0, 95% confidence interval [CI]: 4.9, 9.0; PT, MD = 6.9, 95% CI: 4.7 to 9.1; and education, MD = 3.4, 95% CI: 0.54 to 6.3), with yoga and PT improvements being clinically meaningful. At 12 weeks, improvements in catastrophizing (CSQ, range 0-36) were largest in the yoga and PT groups (MD = -3.0, 95% CI: -4.4 to -1.6; MD = -2.7, 95% CI: -4.2 to -1.2, respectively). Changes in FABQ were small. No statistically significant between-group differences were observed on PSEQ, CSQ, or FABQ at either time point. Many of the changes observed at 12 weeks were sustained at 52 weeks.

CONCLUSION

All three interventions were associated with improvements in self-efficacy and catastrophizing among low-income, racially diverse adults with cLBP.

TRIAL REGISTRATION

ClinicalTrials.gov identifier NCT01343927.

Predicted Vitamin D Status and Colorectal Cancer Incidence in the Black Women's Health Study

BACKGROUND

Observational studies, mostly among White populations, suggest that low vitamin D levels increase colorectal cancer risk. African Americans, who are disproportionately burdened by colorectal cancer, often have lower vitamin D levels compared with other populations.

METHODS

We assessed predicted vitamin D score in relation to colorectal cancer among 49,534 participants in the Black Women's Health Study, a cohort of African American women followed from 1995 to 2017 through biennial questionnaires. We derived predicted vitamin D scores at each questionnaire cycle for all participants using a previously validated prediction model based on actual 25-hydroxyvitamin D values from a subset of participants. We calculated cumulative average predicted vitamin D score at every cycle by averaging scores from cycles up to and including that cycle. Using Cox proportional hazards regression, we estimated hazard ratios (HR) and 95% confidence intervals (CI) for colorectal cancer incidence according to predicted score quartiles.

RESULTS

Over follow-up, 488 incident colorectal cancers occurred. Compared with women in the highest quartile of predicted vitamin D score, those in the lowest had an estimated 41% (HR = 1.41; 95% CI, 1.05-1.90) higher colorectal cancer risk. Comparable HRs were 1.44 (95% CI, 1.02-2.01) for colon and 1.34 (95% CI, 0.70-2.56) for rectal cancer.

CONCLUSIONS

Low vitamin D status may lead to elevated colorectal cancer risk in African American women.

IMPACT

Our findings, taken together with established evidence that vitamin D levels are generally lower in African Americans than other U.S. groups, suggest that low vitamin D status may contribute to the disproportionately high colorectal cancer incidence among African Americans.

Early Convalescent Plasma Therapy and Mortality Among US Veterans Hospitalized With Nonsevere COVID-19: An Observational Analysis Emulating a Target Trial

BACKGROUND

Early convalescent plasma transfusion may reduce mortality in patients with nonsevere coronavirus disease 2019 (COVID-19).

METHODS

This study emulates a (hypothetical) target trial using observational data from a cohort of US veterans admitted to a Department of Veterans Affairs (VA) facility between 1 May and 17 November 2020 with nonsevere COVID-19. The intervention was convalescent plasma initiated within 2 days of eligibility. Thirty-day mortality was compared using cumulative incidence curves, risk differences, and hazard ratios estimated from pooled logistic models with inverse probability weighting to adjust for confounding.

RESULTS

Of 11 269 eligible person-trials contributed by 4755 patients, 402 trials were assigned to the convalescent plasma group. Forty and 671 deaths occurred within the plasma and nonplasma groups, respectively. The estimated 30-day mortality risk was 6.5% (95% confidence interval [CI], 4.0%-9.7%) in the plasma group and 6.2% (95% CI, 5.6%-7.0%) in the nonplasma group. The associated risk difference was 0.30% (95% CI, -2.30% to 3.60%) and the hazard ratio was 1.04 (95% CI, .64-1.62).

CONCLUSIONS

Our target trial emulation estimated no meaningful differences in 30-day mortality between nonsevere COVID-19 patients treated and untreated with convalescent plasma. Clinical Trials Registration. NCT04545047.

Phenome-wide association of 1809 phenotypes and COVID-19 disease progression in the Veterans Health Administration Million Veteran Program

BACKGROUND

The risk factors associated with the stages of Coronavirus Disease-2019 (COVID-19) disease progression are not well known. We aim to identify risk factors specific to each state of COVID-19 progression from SARS-CoV-2 infection through death.

METHODS AND RESULTS

We included 648,202 participants from the Veteran Affairs Million Veteran Program (2011-). We identified characteristics and 1,809 ICD code-based phenotypes from the electronic health record. We used logistic regression to examine the association of age, sex, body mass index (BMI), race, and prevalent phenotypes to the stages of COVID-19 disease progression: infection, hospitalization, intensive care unit (ICU) admission, and 30-day mortality (separate models for each). Models were adjusted for age, sex, race, ethnicity, number of visit months and ICD codes, state infection rate and controlled for multiple testing using false discovery rate (≤0.1). As of August 10, 2020, 5,929 individuals were SARS-CoV-2 positive and among those, 1,463 (25%) were hospitalized, 579 (10%) were in ICU, and 398 (7%) died. We observed a lower risk in women vs. men for ICU and mortality (Odds Ratio (95% CI): 0.48 (0.30-0.76) and 0.59 (0.31-1.15), respectively) and a higher risk in Black vs. Other race patients for hospitalization and ICU (OR (95%CI): 1.53 (1.32-1.77) and 1.63 (1.32-2.02), respectively). We observed an increased risk of all COVID-19 disease states with older age and BMI ≥35 vs. 20-24 kg/m2. Renal failure, respiratory failure, morbid obesity, acid-base balance disorder, white blood cell diseases, hydronephrosis and bacterial infections were associated with an increased risk of ICU admissions; sepsis, chronic skin ulcers, acid-base balance disorder and acidosis were associated with mortality.

CONCLUSIONS

Older age, higher BMI, males and patients with a history of respiratory, kidney, bacterial or metabolic comorbidities experienced greater COVID-19 severity. Future studies to investigate the underlying mechanisms associated with these phenotype clusters and COVID-19 are warranted.

COVID-19 Evidence Accelerator: A parallel analysis to describe the use of Hydroxychloroquine with or without Azithromycin among hospitalized COVID-19 patients

BACKGROUND

The COVID-19 pandemic remains a significant global threat. However, despite urgent need, there remains uncertainty surrounding best practices for pharmaceutical interventions to treat COVID-19. In particular, conflicting evidence has emerged surrounding the use of hydroxychloroquine and azithromycin, alone or in combination, for COVID-19. The COVID-19 Evidence Accelerator convened by the Reagan-Udall Foundation for the FDA, in collaboration with Friends of Cancer Research, assembled experts from the health systems research, regulatory science, data science, and epidemiology to participate in a large parallel analysis of different data sets to further explore the effectiveness of these treatments.

METHODS

Electronic health record (EHR) and claims data were extracted from seven separate databases. Parallel analyses were undertaken on data extracted from each source. Each analysis examined time to mortality in hospitalized patients treated with hydroxychloroquine, azithromycin, and the two in combination as compared to patients not treated with either drug. Cox proportional hazards models were used, and propensity score methods were undertaken to adjust for confounding. Frequencies of adverse events in each treatment group were also examined.

RESULTS

Neither hydroxychloroquine nor azithromycin, alone or in combination, were significantly associated with time to mortality among hospitalized COVID-19 patients. No treatment groups appeared to have an elevated risk of adverse events.

CONCLUSION

Administration of hydroxychloroquine, azithromycin, and their combination appeared to have no effect on time to mortality in hospitalized COVID-19 patients. Continued research is needed to clarify best practices surrounding treatment of COVID-19.

Which Chronic Low Back Pain Patients Respond Favorably to Yoga, Physical Therapy, and a Self-care Book? Responder Analyses from a Randomized Controlled Trial

PURPOSE

To identify baseline characteristics of adults with chronic low back pain (cLBP) that predict response (i.e., a clinically important improvement) and/or modify treatment effect across three nonpharmacologic interventions.

DESIGN

Secondary analysis of a randomized controlled trial.

SETTING

Academic safety net hospital and seven federally qualified community health centers.

SUBJECTS

Adults with cLBP (N = 299).

METHODS

We report patient characteristics that were predictors of response and/or modified treatment effect across three 12-week treatments: yoga, physical therapy [PT], and a self-care book. Using preselected characteristics, we used logistic regression to identify predictors of "response," defined as a ≥30% improvement in the Roland Morris Disability Questionnaire. Then, using "response" as our outcome, we identified baseline characteristics that were treatment effect modifiers by testing for statistical interaction (P < 0.05) across two comparisons: 1) yoga-or-PT vs self-care and 2) yoga vs PT.

RESULTS

Overall, 39% (116/299) of participants were responders, with more responders in the yoga-or-PT group (42%) than the self-care (23%) group. There was no difference in proportion responding to yoga (48%) vs PT (37%, odds ratio [OR] = 1.5, 95% confidence interval = 0.88 - 2.6). Predictors of response included having more than a high school education, a higher income, employment, few depressive symptoms, lower perceived stress, few work-related fear avoidance beliefs, high pain self-efficacy, and being a nonsmoker. Effect modifiers included use of pain medication and fear avoidance beliefs related to physical activity (both P = 0.02 for interaction). When comparing yoga or PT with self-care, a greater proportion were responders among those using pain meds (OR = 5.3), which differed from those not taking pain meds (OR = 0.94) at baseline. We also found greater treatment response among those with lower (OR = 7.0), but not high (OR = 1.3), fear avoidance beliefs around physical activity.

CONCLUSIONS

Our findings revealed important subgroups for whom referral to yoga or PT may improve cLBP outcomes.

Aspirin use and risk of breast cancer in African American women

BACKGROUND

Use of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) has been hypothesized to be associated with reduced risk of breast cancer; however, results of epidemiological studies have been mixed. Few studies have investigated these associations among African American women.

METHODS

To assess the relation of aspirin use to risk of breast cancer in African American women, we conducted a prospective analysis within the Black Women's Health Study, an ongoing nationwide cohort study of 59,000 African American women. On baseline and follow-up questionnaires, women reported regular use of aspirin (defined as use at least 3 days per week) and years of use. During follow-up from 1995 through 2017, 1919 invasive breast cancers occurred, including 1112 ER+, 569 ER-, and 284 triple-negative (TN) tumors. We used age-stratified Cox proportional hazards regression models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of aspirin use with risk of ER+, ER-, and TN breast cancer, adjusted for established breast cancer risk factors.

RESULTS

Overall, the HR for current regular use of aspirin relative to non-use was 0.92 (95% CI 0.81, 1.04). For ER+, ER-, and TN breast cancer, corresponding HRs were 0.98 (0.84, 1.15), 0.81 (0.64, 1.04), and 0.70 (0.49, 0.99), respectively.

CONCLUSIONS

Our findings with regard to ER- and TN breast cancer are consistent with hypothesized inflammatory mechanisms of ER- and TN breast cancer, rather than hormone-dependent pathways. Aspirin may represent a potential opportunity for chemoprevention of ER- and TN breast cancer.

A Prospective Analysis of Intake of Red and Processed Meat in Relation to Pancreatic Cancer among African American Women

BACKGROUND

African Americans have the highest incidence of pancreatic cancer of any racial/ethnic group in the United States. There is evidence that consumption of red or processed meat and foods containing saturated fats may increase the risk of pancreatic cancer, but there is limited evidence in African Americans.

METHODS

Utilizing the Black Women's Health Study (1995-2018), we prospectively investigated the associations of red and processed meat and saturated fats with incidence of pancreatic adenocarcinoma (n = 168). A food frequency questionnaire was completed by 52,706 participants in 1995 and 2001. Multivariable-adjusted HRs and 95% confidence intervals (CI) were estimated using Cox proportional hazards regression. We observed interactions with age (P _interaction = 0.01). Thus, results were stratified at age 50 (<50, ≥50).

RESULTS

Based on 148 cases among women aged ≥50 years, total red meat intake was associated with a 65% increased pancreatic cancer risk (HR_{Q4 vs. Q1} = 1.65; 95% CI, 0.98-2.78; P _trend = 0.05), primarily due to unprocessed red meat. There was also a nonsignificant association between total saturated fat and pancreatic cancer (HR_{Q4 vs. Q1} = 1.85; 95% CI, 0.92-3.72; P _trend = 0.08). Red meat and saturated fat intakes were not associated with pancreatic cancer risk in younger women, and there was no association with processed meat in either age group.

CONCLUSIONS

Red meat-specifically, unprocessed red meat-and saturated fat intakes were associated with an increased risk of pancreatic cancer in African-American women aged 50 and older, but not among younger women.

IMPACT

The accumulating evidence-including now in African-American women-suggests that diet, a modifiable factor, plays a role in the etiology of pancreatic cancer, suggesting opportunities for prevention.

Yoga, Physical Therapy, and Back Pain Education for Sleep Quality in Low-Income Racially Diverse Adults with Chronic Low Back Pain: a Secondary Analysis of a Randomized Controlled Trial

BACKGROUND

Poor sleep is common among adults with chronic low back pain (cLBP), but the influence of cLBP treatments, such as yoga and physical therapy (PT), on sleep quality is under studied.

OBJECTIVE

Evaluate the effectiveness of yoga and PT for improving sleep quality in adults with cLBP.

DESIGN

Secondary analysis of a randomized controlled trial.

SETTING

Academic safety-net hospital and 7 affiliated community health centers.

PARTICIPANTS

A total of 320 adults with cLBP.

INTERVENTION

Twelve weekly yoga classes, 1-on-1 PT sessions, or an educational book.

MAIN MEASURES

Sleep quality was measured using the Pittsburgh Sleep Quality Index (PSQI) global score (0-21) at baseline, 12 weeks, and 52 weeks. Additionally, we also evaluated how the proportion of participants who achieved a clinically meaningful improvement in sleep quality (> 3-point reduction in PSQI) at 12 weeks varied by changes in pain and physical function at 6 weeks.

KEY RESULTS

Among participants (mean age = 46.0, 64% female, 82% non-white), nearly all (92%) reported poor sleep quality (PSQI > 5) at baseline. At 12 weeks, modest improvements in sleep quality were observed among the yoga (PSQI mean difference [MD] = - 1.19, 95% confidence interval [CI] - 1.82, - 0.55) and PT (PSQI MD = - 0.91, 95% CI - 1.61, - 0.20) groups. Participants who reported a ≥ 30% improvement in pain or physical function at 6 weeks, compared with those who improved < 10%, were more likely to be a sleep quality responder at 12 weeks (odds ratio [OR] = 3.51, 95% CI 1.73, 7.11 and OR = 2.16, 95% CI 1.18, 3.95, respectively). Results were similar at 52 weeks.

CONCLUSION

In a sample of adults with cLBP, virtually all with poor sleep quality prior to intervention, modest but statistically significant improvements in sleep quality were observed with both yoga and PT. Irrespective of treatment, clinically important sleep improvements at the end of the intervention were associated with mid-intervention pain and physical function improvements.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT01343927.

Oral Health in Relation to Pancreatic Cancer Risk in African American Women

BACKGROUND

Incidence of pancreatic cancer is higher in African Americans than in U.S. whites. We hypothesized that poor oral health, disproportionately common in African Americans and associated with increased risk of pancreatic cancer in several studies of predominantly white populations, may play a role in this disparity.

METHODS

We examined the relation of self-reported measures of oral health (periodontal disease and adult tooth loss) in relation to pancreatic cancer incidence in the prospective Black Women's Health Study (BWHS). Cox proportional hazard analyses were used to calculate HRs of pancreatic cancer for women with periodontal disease, tooth loss, or both, relative to women who reported neither. Multivariable models adjusted for age, cigarette smoking, body mass index (BMI), type 2 diabetes, and alcohol consumption.

RESULTS

Participants aged 33 to 81 were followed for an average of 9.85 years from 2007 through 2016, with occurrence of 78 incidence cases of pancreatic cancer. Multivariable HRs for pancreatic cancer incidence were 1.77 [95% confidence interval (CI) 0.57-5.49] for periodontal disease with no tooth loss, 2.05 (95% CI, 1.08-3.88) for tooth loss without report of periodontal disease, and 1.58 (95% CI, 0.70-3.57) for both tooth loss and periodontal disease. The HR for loss of at least five teeth, regardless of whether periodontal disease was reported, was 2.20 (95% CI, 1.11-4.33).

CONCLUSIONS

The poor oral health experienced by many African Americans may contribute to their higher incidence of pancreatic cancer.

IMPACT

Future research will assess associations between the oral microbiome and pancreatic cancer risk in this population.

Association of Degree of European Genetic Ancestry With Serum Vitamin D Levels in African Americans

Circulating levels of vitamin D are generally lower in African Americans than in US whites, and 1 prior analysis carried out in a small number of African Americans suggested that, within this population, vitamin D levels may be related to the degree of genetic admixture. We assessed the association between percentage of European ancestry and serum vitamin D level (assessed in 2013-2015) among 2,183 African-American women from the Black Women's Health Study whose DNA had been genotyped for ancestry-informative markers. ADMIXMAP software was used to estimate the percentage of European ancestry versus African ancestry in each individual. In linear regression analyses with adjustment for genotype batch, age, body mass index, supplemental vitamin D use, ultraviolet B radiation flux in the participant's state of residence, and season of blood draw, each 10% increase in European ancestry was associated with a 0.67-ng/mL increase in serum vitamin D concentration (95% confidence interval: 0.17, 1.17). The association was statistically significant only among women who were not taking vitamin D supplements (for each 10% increase in European ancestry, β = 0.86, 95% confidence interval: 0.14, 1.57). Among African Americans, use of vitamin D supplements may help to reduce vitamin D deficiency associated with genetic ancestry.

Abstract 5247: Aspirin use and estrogen receptor-negative breast cancer risk in African American women

Introduction: Use of aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) has been hypothesized to be associated with reduced risk of breast cancer; however, results of epidemiological studies have been mixed. Further, few previous studies investigated these associations among African American women and no studies that included African Americans evaluated whether associations differ by estrogen receptor (ER) status.

Methods: To assess the relation of aspirin use to risk of ER+ and ER- breast cancer in African American women, we conducted a prospective analysis within the Black Women's Health Study, an ongoing nationwide cohort of 59,000 black women that began in 1995. On baseline and biennial follow-up questionnaires, women reported regular aspirin use (defined as use at least three days per week) and years of use. Acetaminophen use was queried similarly. Among women with available information on aspirin use, 1701 invasive breast cancers occurred during follow-up through 2015, including 962 ER+ and 492 ER- tumors. All cancers were confirmed through pathology reports or state cancer registry data. We used age-stratified Cox proportional hazards regression models to estimate multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for associations of aspirin use with risk of ER+ and ER- breast cancer. All models adjusted for age at menarche, oral contraceptive use, parity, age at first birth, estrogen plus progestin use, body mass index, alcohol consumption, and use of other NSAIDs.

Results: Compared to never use, current regular use of aspirin was associated with lower risk of breast cancer overall (HR 0.87; 95% CI 0.76, 1.00). The association was driven by a statistically significant inverse association for ER- breast cancer (HR 0.76; 95% CI 0.58, 0.99); for ER+ breast cancer, the corresponding HR was 0.92 (95% CI 0.77, 1.09). In contrast, we found no associations with acetaminophen use.

Conclusions: Our observation of reduced risk of ER- breast cancer in relation to current regular use of aspirin is consistent with anti-inflammatory effects of aspirin, rather than hormone-dependent pathways. Aspirin may represent a potential opportunity for chemoprevention of ER- breast cancer; however, these findings require corroboration in additional studies.

Citation Format: Kimberly A. Bertrand, Traci N. Bethea, Hanna Gerlovin, Patricia Coogan, Lucile L. Adams-Campbell, Lynn Rosenberg, Julie R. Palmer. Aspirin use and estrogen receptor-negative breast cancer risk in African American women [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5247.

Pubertal growth and adult height in relation to breast cancer risk in African American women

Adult height has been positively associated with breast cancer risk. The timing of pubertal growth-as measured by age at menarche and age at attained height-may also influence risk. We evaluated associations of adult height, age at attained height, and age at menarche with incidence of invasive breast cancer in 55,687 African American women in the prospective Black Women's Health Study. Over 20 years, 1,826 invasive breast cancers [1,015 estrogen receptor (ER) positive; 542 ER negative] accrued. We used multivariable Cox proportional hazards regression to estimate hazards ratios (HRs) and 95% confidence intervals (CIs) for associations with breast cancer overall and by ER status, mutually adjusted for the three factors of interest. Adult height was associated with increased risk of ER+ breast cancer (HR for ≥70 inches vs ≤63 inches: 1.44; 95% CI: 1.09, 1.89) but not ER- (corresponding HR: 1.16; 95% CI: 0.78, 1.71) (p heterogeneity = 0.34). HRs for attained height before age 13 versus age >17 were 1.30 (95% CI: 0.96, 1.76) for ER+ and 1.25 (95% CI: 0.80, 1.96) for ER- breast cancer. Results for age at menarche (≤11 vs ≥14 years) were similar for ER+ and ER- breast cancer (HR for breast cancer overall: 1.30; 95% CI: 1.12, 1.50). We confirmed height as a strong risk factor for ER+ breast cancer in African American women and identified early age at attained height as a risk factor for both ER+ and ER- breast cancer, albeit without statistical significance of the latter associations. While adult height and timing of pubertal growth are inter-related, our findings suggest that they may be independent risk factors for breast cancer.

Predicted 25-hydroxyvitamin D in relation to incidence of breast cancer in a large cohort of African American women

BACKGROUND

Vitamin D deficiency, which has been linked to an increased risk of colorectal cancer, is particularly common among African Americans. Previous studies of vitamin D status and breast cancer risk, mostly conducted in white women, have had conflicting results. We examined the relationship between predicted vitamin D status and incidence of breast cancer in a cohort of 59,000 African American women.

METHODS

Participants in the Black Women's Health Study have been followed by biennial mail questionnaires since 1995, with self-reported diagnoses of cancer confirmed by hospital and cancer registry records. Repeated five-fold cross-validation with linear regression was used to derive the best 25-hydroxyvitamin D (25(OH)D) prediction model based on measured 25(OH)D in plasma specimens obtained from 2856 participants in 2013-2015 and questionnaire-based variables from the same time frame. In the full cohort, including 1454 cases of incident invasive breast cancer, Cox proportional hazards models were used to compute the incidence rate ratio (IRR) for each quartile of predicted vitamin D score relative to the highest quartile. Predicted vitamin D score for each two-year exposure period was a cumulative average of predicted scores from all exposure periods up to that time.

RESULTS

Twenty-two percent of women with measured 25(OH)D were categorized as "deficient" (<20 ng/mL) and another 25 % as "insufficient" (20-29 ng/mL). The prediction model explained 25 % of variation in measured 25(OH)D and the correlation coefficient for predicted versus observed 25(OH)D averaged across all cross-validation runs was 0.49 (SD 0.026). Breast cancer risk increased with decreasing quartile of predicted 25(OH)D, p for trend 0.015; the IRR for the lowest versus highest quartile was 1.23 (95 % confidence interval 1.04, 1.46).

CONCLUSIONS

In prospective data, African American women in the lowest quartile of cumulative predicted 25(OH)D were estimated to have a 23 % increased risk of breast cancer relative to those with relatively high levels. Preventing vitamin D deficiency may be an effective means of reducing breast cancer incidence in African American women.

Night-shift work and incident diabetes among African-American women

AIMS/HYPOTHESIS

The aim of this study was to assess shift work in relation to incident type 2 diabetes in African-American women.

METHODS

In the Black Women's Health Study (BWHS), an ongoing prospective cohort study, we followed 28,041 participants for incident diabetes during 2005-2013. They answered questions in 2005 about having worked a night shift. We estimated HR and 95% CIs for incident diabetes using Cox proportional hazards models. The basic multivariable model included age, time period, family history of diabetes, education and neighbourhood socioeconomic status. In further models, we controlled for lifestyle factors and BMI.

RESULTS

Over the 8 years of follow-up, there were 1,786 incident diabetes cases. Relative to never having worked the night shift, HRs (95% CI) for diabetes were 1.17 (1.04, 1.31) for 1-2 years of night-shift work, 1.23 (1.06, 1.41) for 3-9 years and 1.42 (1.19, 1.70) for ≥ 10 years (p-trend < 0.0001). The monotonic positive association between night-shift work and type 2 diabetes remained after multivariable adjustment (p-trend = 0.02). The association did not vary by obesity status, but was stronger in women aged <50 years.

CONCLUSIONS/INTERPRETATION

Long duration of shift work was associated with an increased risk of type 2 diabetes. The association was only partially explained by lifestyle factors and BMI. A better understanding of the mechanisms by which shift work may affect the risk of diabetes is needed in view of the high prevalence of shift work among workers in the USA.

Birth weight and risk of type 2 diabetes in the black women's health study: does adult BMI play a mediating role?

OBJECTIVE

To assess the association of birth weight with incident type 2 diabetes, and the possible mediating influence of obesity, in a large cohort of U.S. black women.

RESEARCH DESIGN AND METHODS

The Black Women's Health Study is an ongoing prospective study. We used Cox proportional hazards models to estimate incidence rate ratios (IRRs) and 95% CI for categories of birth weight (very low birth weight [<1,500 g], low birth weight [1,500-2,499 g], and high birth weight [≥4,000 g]) in reference to normal birth weight (2,500-3,999 g). Models were adjusted for age, questionnaire cycle, family history of diabetes, caloric intake, preterm birth, physical activity, years of education, and neighborhood socioeconomic status with and without inclusion of terms for adult BMI.

RESULTS

We followed 21,624 women over 16 years of follow-up. There were 2,388 cases of incident diabetes. Women with very low birth weight had a 40% higher risk of disease (IRR 1.40 [95% CI 1.08-1.82]) than women with normal birth weight; women with low birth weight had a 13% higher risk (IRR 1.13 [95% CI 1.02-1.25]). Adjustment for BMI did not appreciably change the estimates.

CONCLUSIONS

Very low birth weight and low birth weight appear to be associated with increased risk of type 2 diabetes in African American women, and the association does not seem to be mediated through BMI. The prevalence of low birth weight is especially high in African American populations, and this may explain in part the higher occurrence of type 2 diabetes.

Depressive symptoms, antidepressant use, and the incidence of diabetes in the Black Women's Health Study

OBJECTIVE

To assess the relationship of depressive symptoms and use of antidepressants with incident type 2 diabetes in prospective data from a large cohort of U.S. African American women.

RESEARCH DESIGN AND METHODS

The Black Women's Health Study (BWHS) is an ongoing prospective cohort study. We followed 35,898 women from 1999 through 2011 who were without a diagnosis of diabetes and who had completed the Center for Epidemiologic Studies Depression Scale (CES-D) in 1999. CES-D scores were categorized as <16, 16-22, 23-32, and ≥33, which reflected increasingly more depressive symptoms. We estimated incidence rate ratios (IRRs) and 95% CIs for incident diabetes using Cox proportional hazards models. The basic multivariable model included age, time period, family history of diabetes, and education. In further models, we controlled for lifestyle factors and BMI. We also assessed the association of antidepressant use with incident diabetes.

RESULTS

Over 12 years of follow-up, there were 3,372 incident diabetes cases. Relative to CES-D score <16, IRRs (95% CI) of diabetes for CES-D scores 16-22, 23-32, and ≥33 were 1.23 (1.12-1.35), 1.26 (1.12-1.41), and 1.45 (1.24-1.69), respectively, in the basic multivariate model. Multiple adjustment for lifestyle factors and BMI attenuated the IRRs to 1.11 (1.01-1.22), 1.08 (0.96-1.22), and 1.22 (1.04-1.43). The adjusted IRR for antidepressant use was 1.26 (1.11-1.43). Results were similar among obese women.

CONCLUSIONS

Both depressive symptoms and antidepressant use are associated with incident diabetes among African American women. These associations are mediated in part, but not entirely, through lifestyle factors and BMI.

Impact of obesity and knee osteoarthritis on morbidity and mortality in older Americans

BACKGROUND

Obesity and knee osteoarthritis are among the most frequent chronic conditions affecting Americans aged 50 to 84 years.

OBJECTIVE

To estimate quality-adjusted life-years lost due to obesity and knee osteoarthritis and health benefits of reducing obesity prevalence to levels observed a decade ago.

DESIGN

The U.S. Census and obesity data from national data sources were combined with estimated prevalence of symptomatic knee osteoarthritis to assign persons aged 50 to 84 years to 4 subpopulations: nonobese without knee osteoarthritis (reference group), nonobese with knee osteoarthritis, obese without knee osteoarthritis, and obese with knee osteoarthritis. The Osteoarthritis Policy Model, a computer simulation model of knee osteoarthritis and obesity, was used to estimate quality-adjusted life-year losses due to knee osteoarthritis and obesity in comparison with the reference group.

SETTING

United States.

PARTICIPANTS

U.S. population aged 50 to 84 years.

MEASUREMENTS

Quality-adjusted life-years lost owing to knee osteoarthritis and obesity.

RESULTS

Estimated total losses of per-person quality-adjusted life-years ranged from 1.857 in nonobese persons with knee osteoarthritis to 3.501 for persons affected by both conditions, resulting in a total of 86.0 million quality-adjusted life-years lost due to obesity, knee osteoarthritis, or both. Quality-adjusted life-years lost due to knee osteoarthritis and/or obesity represent 10% to 25% of the remaining quality-adjusted survival of persons aged 50 to 84 years. Hispanic and black women had disproportionately high losses. Model findings suggested that reversing obesity prevalence to levels seen 10 years ago would avert 178,071 cases of coronary heart disease, 889,872 cases of diabetes, and 111,206 total knee replacements. Such a reduction in obesity would increase the quantity of life by 6,318,030 years and improve life expectancy by 7,812,120 quality-adjusted years in U.S. adults aged 50 to 84 years.

LIMITATIONS

Comorbidity incidences were derived from prevalence estimates on the basis of life expectancy of the general population, potentially resulting in conservative underestimates. Calibration analyses were conducted to ensure comparability of model-based projections and data from external sources.

CONCLUSION

The number of quality-adjusted life-years lost owing to knee osteoarthritis and obesity seems to be substantial, with black and Hispanic women experiencing disproportionate losses. Reducing mean body mass index to the levels observed a decade ago in this population would yield substantial health benefits.

PRIMARY FUNDING SOURCE

The National Institutes of Health and the Arthritis Foundation.

Impact of obesity and knee osteoarthritis on morbidity and mortality in older Americans

BACKGROUND

Obesity and knee osteoarthritis are among the most frequent chronic conditions affecting Americans aged 50 to 84 years.

OBJECTIVE

To estimate quality-adjusted life-years lost due to obesity and knee osteoarthritis and health benefits of reducing obesity prevalence to levels observed a decade ago.

DESIGN

The U.S. Census and obesity data from national data sources were combined with estimated prevalence of symptomatic knee osteoarthritis to assign persons aged 50 to 84 years to 4 subpopulations: nonobese without knee osteoarthritis (reference group), nonobese with knee osteoarthritis, obese without knee osteoarthritis, and obese with knee osteoarthritis. The Osteoarthritis Policy Model, a computer simulation model of knee osteoarthritis and obesity, was used to estimate quality-adjusted life-year losses due to knee osteoarthritis and obesity in comparison with the reference group.

SETTING

United States.

PARTICIPANTS

U.S. population aged 50 to 84 years.

MEASUREMENTS

Quality-adjusted life-years lost owing to knee osteoarthritis and obesity.

RESULTS

Estimated total losses of per-person quality-adjusted life-years ranged from 1.857 in nonobese persons with knee osteoarthritis to 3.501 for persons affected by both conditions, resulting in a total of 86.0 million quality-adjusted life-years lost due to obesity, knee osteoarthritis, or both. Quality-adjusted life-years lost due to knee osteoarthritis and/or obesity represent 10% to 25% of the remaining quality-adjusted survival of persons aged 50 to 84 years. Hispanic and black women had disproportionately high losses. Model findings suggested that reversing obesity prevalence to levels seen 10 years ago would avert 178,071 cases of coronary heart disease, 889,872 cases of diabetes, and 111,206 total knee replacements. Such a reduction in obesity would increase the quantity of life by 6,318,030 years and improve life expectancy by 7,812,120 quality-adjusted years in U.S. adults aged 50 to 84 years.

LIMITATIONS

Comorbidity incidences were derived from prevalence estimates on the basis of life expectancy of the general population, potentially resulting in conservative underestimates. Calibration analyses were conducted to ensure comparability of model-based projections and data from external sources.

CONCLUSION

The number of quality-adjusted life-years lost owing to knee osteoarthritis and obesity seems to be substantial, with black and Hispanic women experiencing disproportionate losses. Reducing mean body mass index to the levels observed a decade ago in this population would yield substantial health benefits.

PRIMARY FUNDING SOURCE

The National Institutes of Health and the Arthritis Foundation.

Forecasting the burden of advanced knee osteoarthritis over a 10-year period in a cohort of 60-64 year-old US adults

OBJECTIVE

To forecast the burden of symptomatic knee osteoarthritis (OA) in the elderly US population over a 10-year horizon.

DESIGN

Using a computer simulation model of the natural history and management of knee OA combined with population-based data from the 2008 US Census we projected the 10-year burden of knee OA among persons 60-64 years of age. Knee OA incidence and progression rates were derived from national cohorts and calibrated to published literature.

RESULTS

Using national data we estimated that 13% of 14,338,292 adults 60-64 years old have prevalent symptomatic, radiographic knee OA. Among persons surviving the next decade, 20% will have symptomatic advanced (Kellgren-Lawrence [K-L] grade 3) or end-stage (K-L 4) knee OA. Prevalence of advanced knee OA will range from 10% among non-obese to 35% among obese persons. Our estimates show that a more sensitive imaging tool, such as magnetic resonance imaging (MRI), may increase the number of OA cases diagnosed by up to 94% assuming that 50% of all 'pre-radiographic knee OA' (K-L 1) has some evidence of cartilage degeneration seen on MRI.

CONCLUSIONS

Projecting new and advanced cases of knee OA among persons aged 60-64 years over the next decade creates a benchmark that can be used to evaluate population-based benefits of future disease-modifying OA drugs that are currently undergoing testing at various stages.