Identification and outcomes of KDIGO-defined chronic kidney disease in 1.4 million U.S. Veterans with heart failure

AIMS

According to the Kidney Disease: Improving Global Outcomes (KDIGO) guideline, the definition of chronic kidney disease (CKD) requires the presence of abnormal kidney structure or function for >3 months with implications for health. CKD in patients with heart failure (HF) has not been defined using this definition, and less is known about the true health implications of CKD in these patients. The objective of the current study was to identify patients with HF who met KDIGO criteria for CKD and examine their outcomes.

METHODS AND RESULTS

Of the 1 419 729 Veterans with HF not receiving kidney replacement therapy, 828 744 had data on ≥2 ambulatory serum creatinine >90 days apart. CKD was defined as estimated glomerular filtration rate (eGFR) <60 ml/min/1.73 m2 (n = 185 821) or urinary albumin-to-creatinine ratio (uACR) >30 mg/g (n = 32 730) present twice >3 months apart. Normal kidney function (NKF) was defined as eGFR ≥60 ml/min/1.73 m2, present for >3 months, without any uACR >30 mg/g (n = 365 963). Patients with eGFR <60 ml/min/1.73 m2 were categorized into four stages: 45-59 (n = 72 606), 30-44 (n = 74 812), 15-29 (n = 32 077), and <15 (n = 6326) ml/min/1.73 m2. Five-year all-cause mortality occurred in 40.4%, 57.8%, 65.6%, 73.3%, 69.7%, and 47.5% of patients with NKF, four eGFR stages, and uACR >30mg/g (albuminuria), respectively. Compared with NKF, hazard ratios (HR) (95% confidence intervals [CI]) for all-cause mortality associated with the four eGFR stages and albuminuria were 1.63 (1.62-1.65), 2.00 (1.98-2.02), 2.49 (2.45-2.52), 2.28 (2.21-2.35), and 1.22 (1.20-1.24), respectively. Respective age-adjusted HRs (95% CIs) were 1.13 (1.12-1.14), 1.36 (1.34-1.37), 1.87 (1.84-1.89), 2.24 (2.18-2.31) and 1.19 (1.17-1.21), and multivariable-adjusted HRs (95% CIs) were 1.11 (1.10-1.12), 1.24 (1.22-1.25), 1.46 (1.43-1.48), 1.42 (1.38-1.47), and 1.13 (1.11-1.16). Similar patterns were observed for associations with hospitalizations.

CONCLUSION

Data needed to define CKD using KDIGO criteria were available in six out of ten patients, and CKD could be defined in seven out of ten patients with data. HF patients with KDIGO-defined CKD had higher risks for poor outcomes, most of which was not explained by abnormal kidney structure or function. Future studies need to examine whether CKD defined using a single eGFR is characteristically and prognostically different from CKD defined using KDIGO criteria.

Cardiorespiratory fitness and risk of Alzheimer's disease and related dementias among American veterans

INTRODUCTION

Cardiorespiratory fitness (CRF) is associated with improved health and survival. Less is known about its association with Alzheimer's disease and related dementias (ADRD).

METHODS

We identified 649,605 US veterans 30 to 95 years of age and free of ADRD who completed a standardized exercise tolerance test between 2000 and 2017 with no evidence of ischemia. We examined the association between five age- and sex-specific CRF categories and ADRD incidence using multivariate Cox regression models.

RESULTS

During up to 20 (median 8.3) years of follow-up, incident ADRD occurred in 44,105 (6.8%) participants, with an incidence rate of 7.7/1000 person-years. Compared to the least-fit, multivariable-adjusted hazard ratios (95% confidence intervals) for incident ADRD were: 0.87 (0.85-0.90), 0.80 (0.78-0.83), 0.74 (0.72-0.76), and 0.67 (0.65-0.70), for low-fit, moderate-fit, fit, and high-fit individuals, respectively.

DISSCUSSION

These findings demonstrate an independent, inverse, and graded association between CRF and incident ADRD. Future studies may determine the amount and duration of physical activity needed to optimize ADRD risk reduction.

Impact of the COVID-19 Pandemic on the Provision of Dialysis Service and Mortality in Veterans Receiving Maintenance Hemodialysis in the VA: An Interrupted Time-Series Analysis

INTRODUCTION

According to the US Renal Data System (USRDS), patients with end-stage kidney disease (ESKD) on maintenance dialysis had higher mortality during early COVID-19 pandemic. Less is known about the effect of the pandemic on the delivery of outpatient maintenance hemodialysis and its impact on death. We examined the effect of pandemic-related disruption on the delivery of dialysis treatment and mortality in patients with ESKD receiving maintenance hemodialysis in the Veterans Health Administration (VHA) facilities, the largest integrated national healthcare system in the USA.

METHODS

Using national VHA electronic health records data, we identified 7,302 Veterans with ESKD who received outpatient maintenance hemodialysis in VHA healthcare facilities during the COVID-19 pandemic (February 1, 2020, to December 31, 2021). We estimated the average change in the number of hemodialysis treatments received and deaths per 1,000 patients per month during the pandemic by conducting interrupted time-series analyses. We used seasonal autoregressive moving average (SARMA) models, in which February 2020 was used as the conditional intercept and months thereafter as conditional slope. The models were adjusted for seasonal variations and trends in rates during the pre-pandemic period (January 1, 2007, to January 31, 2020).

RESULTS

The number (95% CI) of hemodialysis treatments received per 1,000 patients per month during the pre-pandemic and pandemic periods were 12,670 (12,525-12,796) and 12,865 (12,729-13,002), respectively. Respective all-cause mortality rates (95% CI) were 17.1 (16.7-17.5) and 19.6 (18.5-20.7) per 1,000 patients per month. Findings from SARMA models demonstrate that there was no reduction in the dialysis treatments delivered during the pandemic (rate ratio: 0.999; 95% CI: 0.998-1.001), but there was a 2.3% (95% CI: 1.5-3.1%) increase in mortality. During the pandemic, the non-COVID hospitalization rate was 146 (95% CI: 143-149) per 1,000 patients per month, which was lower than the pre-pandemic rate of 175 (95% CI: 173-176). In contrast, there was evidence of higher use of telephone encounters during the pandemic (3,023; 95% CI: 2,957-3,089), compared with the pre-pandemic rate (1,282; 95% CI: 1,241-1,324).

CONCLUSIONS

We found no evidence that there was a disruption in the delivery of outpatient maintenance hemodialysis treatment in VHA facilities during the COVID-19 pandemic and that the modest rise in deaths during the pandemic is unlikely to be due to missed dialysis.

Hydroxychloroquine and Risk of Long QT Syndrome in Rheumatoid Arthritis: A Veterans Cohort Study With Nineteen-Year Follow-up

OBJECTIVE

Recent evidence suggests that hydroxychloroquine use is not associated with higher 1-year risk of long QT syndrome (LQTS) in patients with rheumatoid arthritis (RA). Less is known about its long-term risk, the examination of which was the objective of this study.

METHODS

We conducted a propensity score-matched active-comparator safety study of hydroxychloroquine in 8,852 veterans (mean age 64 ± 12 years, 14% women, 28% Black) with newly diagnosed RA. A total of 4,426 patients started on hydroxychloroquine and 4,426 started on another nonbiologic disease-modifying antirheumatic drug (DMARD) and were balanced on 87 baseline characteristics. The primary outcome was LQTS during 19-year follow-up through December 31, 2019.

RESULTS

Incident LQTS occurred in 4 (0.09%) and 5 (0.11%) patients in the hydroxychloroquine and other DMARD groups, respectively, during the first 2 years. Respective 5-year incidences were 17 (0.38%) and 6 (0.14%), representing 11 additional LQTS events in the hydroxychloroquine group (number needed to harm 403; [95% confidence interval (95% CI)], 217-1,740) and a 181% greater relative risk (95% CI 11%-613%; P = 0.030). Although overall 10-year risk remained significant (hazard ratio 2.17; 95% CI 1.13-4.18), only 5 extra LQTS occurred in hydroxychloroquine group over the next 5 years (years 6-10) and 1 over the next 9 years (years 11-19). There was no association with arrhythmia-related hospitalization or all-cause mortality.

CONCLUSIONS

Hydroxychloroquine use had no association with LQTS during the first 2 years after initiation of therapy. There was a higher risk thereafter that became significant after 5 years of therapy. However, the 5-year absolute risk was very low, and the absolute risk difference was even lower. Both risks attenuated during longer follow-up. These findings provide evidence for long-term safety of hydroxychloroquine in patients with RA.

Assessment of Lung Cancer Risk Among Smokers for Whom Annual Screening Is Not Recommended

Importance

The US Preventive Services Task Force does not recommend annual lung cancer screening with low-dose computed tomography (LDCT) for adults aged 50 to 80 years who are former smokers with 20 or more pack-years of smoking who quit 15 or more years ago or current smokers with less than 20 pack-years of smoking.

Objective

To determine the risk of lung cancer in older smokers for whom LDCT screening is not recommended.

Design, Settings, and Participants

This cohort study used the Cardiovascular Health Study (CHS) data sets obtained from the National Heart, Lung and Blood Institute, which also sponsored the study. The CHS enrolled 5888 community-dwelling individuals aged 65 years and older in the US from June 1989 to June 1993 and collected extensive baseline data on smoking history. The current analysis was restricted to 4279 individuals free of cancer who had baseline data on pack-year smoking history and duration of smoking cessation. The current analysis was conducted from January 7, 2022, to May 25, 2022.

Exposures

Current and prior tobacco use.

Main Outcomes and Measures

Incident lung cancer during a median (IQR) of 13.3 (7.9-18.8) years of follow-up (range, 0 to 22.6) through December 31, 2011. A Fine-Gray subdistribution hazard model was used to estimate incidence of lung cancer in the presence of competing risk of death. Cox cause-specific hazard regression models were used to estimate hazard ratios (HRs) and 95% CIs for incident lung cancer.

Results

There were 4279 CHS participants (mean [SD] age, 72.8 [5.6] years; 2450 [57.3%] women; 663 [15.5%] African American, 3585 [83.8%] White, and 31 [0.7%] of other race or ethnicity) included in the current analysis. Among the 861 nonheavy smokers (<20 pack-years), the median (IQR) pack-year smoking history was 7.6 (3.3-13.5) pack-years for the 615 former smokers with 15 or more years of smoking cessation, 10.0 (5.3-14.9) pack-years for the 146 former smokers with less than 15 years of smoking cessation, and 11.4 (7.3-14.4) pack-years for the 100 current smokers. Among the 1445 heavy smokers (20 or more pack-years), the median (IQR) pack-year smoking history was 34.8 (26.3-48.0) pack-years for the 516 former smokers with 15 or more years of smoking cessation, 48.0 (35.0-70.0) pack-years for the 497 former smokers with less than 15 years of smoking cessation, and 48.8 (31.6-57.0) pack-years for the 432 current smokers. Incident lung cancer occurred in 10 of 1973 never smokers (0.5%), 5 of 100 current smokers with less than 20 pack-years of smoking (5.0%), and 26 of 516 former smokers with 20 or more pack-years of smoking with 15 or more years of smoking cessation (5.0%). Compared with never smokers, cause-specific HRs for incident lung cancer in the 2 groups for whom LDCT is not recommended were 10.54 (95% CI, 3.60-30.83) for the current nonheavy smokers and 11.19 (95% CI, 5.40-23.21) for the former smokers with less than 15 years of smoking cessation; age, sex, and race-adjusted HRs were 10.06 (95% CI, 3.41-29.70) for the current nonheavy smokers and 10.22 (4.86-21.50) for the former smokers with less than 15 years of smoking cessation compared with never smokers.

Conclusions and Relevance

The findings of this cohort study suggest that there is a high risk of lung cancer among smokers for whom LDCT screening is not recommended, suggesting that prediction models are needed to identify high-risk subsets of these smokers for screening.

Beta-Blocker Use and Outcomes in Nursing Home Residents with Heart Failure with Reduced Ejection Fraction

BACKGROUND

Beta-blockers improve clinical outcomes in patients with heart failure with reduced ejection fraction (HFrEF). Less is known about their role in older nursing home residents with HFrEF.

METHODS

From the combined OPTIMIZE-HF and Alabama Heart Failure Project data sets, we assembled a propensity score-matched balanced cohort of 6494 hospitalized patients ≥65 years with HFrEF (ejection fraction ≤40%). In our primary approach, hazard ratios (HRs) and 95% confidence intervals (CI)s for outcomes associated with discharge prescriptions for beta- blockers were estimated, examining for heterogeneity by admission from nursing homes. In our sensitivity approach, we examined these associations in a separately assembled propensity score-matched cohort of 122 patients admitted from nursing homes.

RESULTS

In the matched primary cohort of 6494 patients, HRs (95% CIs) for 12-month all-cause mortality and heart failure readmission were 0.80 (0.74-0.87) and 0.94 (0.86-1.02), respectively. Respective HRs (95% CIs) in the nursing home and non-nursing home subgroups were 0.77 (0.51-1.16) and 0.81 (0.74-0.87) for all-cause mortality (interaction P: 0.653) and 1.06 (0.53-2.12) and 0.89 (0.82-0.96) for heart failure readmission (interaction P: 0.753). In the matched sensitivity cohort of 122 patients admitted from nursing homes, HRs (95% CIs) for 12-month all-cause mortality and heart failure readmission were 0.86 (0.55-1.35) and 1.07 (0.52-2.22), respectively. Similar associations were observed for 30-day outcomes.

CONCLUSIONS

Beta-blocker use was associated with a lower risk of all-cause mortality but not of heart failure readmission in older patients with HFrEF, which were similar for patients admitted and not admitted from nursing homes.

Cardiovascular Safety of Hydroxychloroquine in US Veterans With Rheumatoid Arthritis

OBJECTIVE

Hydroxychloroquine (HCQ) may prolong the QT interval, a risk factor for torsade de pointes, a potentially fatal ventricular arrhythmia. This study was undertaken to examine the cardiovascular safety of HCQ in patients with rheumatoid arthritis (RA).

METHODS

We conducted an active comparator safety study of HCQ in a propensity score-matched cohort of 8,852 US veterans newly diagnosed as having RA between October 1, 2001 and December 31, 2017. Patients were started on HCQ (n = 4,426) or another nonbiologic disease-modifying antirheumatic drug (DMARD; n = 4,426) after RA diagnosis, up to December 31, 2018, and followed up for 12 months after therapy initiation, up to December 31, 2019.

RESULTS

Patients had a mean ± SD age of 64 ± 12 years, 14% were women, and 28% were African American. The treatment groups were balanced with regard to 87 baseline characteristics. There were 3 long QT syndrome events (0.03%), 2 of which occurred in patients receiving HCQ. Of the 56 arrhythmia-related hospitalizations (0.63%), 30 occurred in patients in the HCQ group (hazard ratio [HR] associated with HCQ 1.16 [95% confidence interval (95% CI) 0.68-1.95]). All-cause mortality occurred in 144 (3.25%) and 136 (3.07%) of the patients in the HCQ and non-HCQ groups, respectively (HR associated with HCQ 1.06 [95% CI, 0.84-1.34]). During the first 30 days of follow-up, there were no long QT syndrome events, 2 arrhythmia-related hospitalizations (none in the HCQ group), and 13 deaths (6 in the HCQ group).

CONCLUSION

Our findings indicate that the incidence of long QT syndrome and arrhythmia-related hospitalization is low in patients with RA during the first year after the initiation of HCQ or another nonbiologic DMARD. We found no evidence that HCQ therapy is associated with a higher risk of adverse cardiovascular events or death.

Alzheimer's Disease and Alzheimer's Disease-Related Dementias in Older African American and White Veterans

BACKGROUND

Racial disparity in the epidemiology of Alzheimer's disease and Alzheimer's disease-related dementias (AD/ADRD) has been reported. However, less is known about this disparity among Veterans.

OBJECTIVE

To estimate the racial disparity in AD/ADRD among the Veterans.

METHODS

Of the 5,413,418 Veterans≥65 years receiving care at the Veterans Health Administration (1999-2016), 4,045,269 were free of prevalent AD/ADRD, schizophrenia, or bipolar disorder at baseline. Of these, 432,469 were African American. Race was self-identified and incident AD/ADRD during 20 (median 6.7) years of follow-up was ascertained using International Classification of Diseases codes.

RESULTS

Patients had a mean age of 70.4 (±6.6) years and 97.8% were men. Age-sex-adjusted incidence of AD/ADRD per 1,000 person-year was 19.3 and 10.8 for African American and white Veterans, respectively (age-sex-adjusted hazard ratio associated with African American race, 1.77; 95% confidence interval, 1.75-1.79; p < 0.0001). This association remained essentially unchanged after multivariable adjustment (hazard ratio, 1.67; 95% confidence interval, 1.65-1.69; p < 0.0001). Among the key baseline characteristics that were significant predictors of AD/ADRD in both races, stroke was a significantly stronger predictor among African Americans, and Hispanic ethnicity and depression among whites (p-value for all interaction,<0.0001).

CONCLUSION

The findings of a higher incidence of AD/ADRD among African American Veterans is consistent with the findings in the general population reported in the literature, although the overall incidence appears to be lower than that in the general population. Future studies need to examine this disparity in incidence as well as the between-race heterogeneity in AD/ADRD risk.

Renin-Angiotensin Inhibition and Outcomes in Nursing Home Residents With Heart Failure

BACKGROUND

Angiotensin-converting enzyme inhibitors or angiotensin receptor blockers (ACEIs-ARBs) improve outcomes in heart failure (HF). Less is known about this association in nursing home (NH) residents.

METHODS

Of the 8024 hospitalized HF patients, 542 were NH residents, of whom 250 received ACEIs-ARBs. We assembled a propensity score-matched cohort of 157 pairs of NH residents receiving and not receiving ACEIs-ARBs balanced on 29 baseline characteristics (mean age, 83 years, 74% women, 17% African American), in which we estimated hazard ratios (HRs) and 95% confidence intervals (CIs) for outcomes associated with ACEI-ARB use. We then checked for interaction in a matched cohort of 5130 patients (378 were NH residents) assembled from the 8024 patients.

RESULTS

Among 314 matched NH residents, HRs (95% CIs) for 30-day all-cause readmission, HF readmission, and all-cause mortality were 0.78 (0.47-1.28), 0.68 (0.29-1.60), and 1.26 (0.70-2.27), respectively. Respective HRs (95% CIs) at 1 year were 0.76 (0.56-1.02), 0.68 (0.42-1.09), and 1.04 (0.78-1.38). Among 5130 matched patients, ACEI-ARB use was associated with a significantly lower risk of all outcomes at both times, with no significant interactions, except for 1-year mortality, which was only significant in the non-NH subgroup (P for interaction, 0.026).

CONCLUSIONS

We found no evidence that the use of ACEIs or ARBs is associated with improved outcomes in patients with HF in the NH setting. However, we also found no evidence that this association is different in NH residents with HF versus non-NH patients with HF. Future larger studies are needed to demonstrate effectiveness of these drugs in the NH setting.

Length of stay and readmission in older adults hospitalized for heart failure

INTRODUCTION

Hospital length of stay (LoS) and hospital readmissions are metrics of healthcare performance. We examined the association between these two metrics in older patients hospitalized with decompensated heart failure (HF).

MATERIAL AND METHODS

Eight thousand and forty-nine patients hospitalized for HF in 106 U.S. hospitals had a median LoS of 5 days; among them, 3777 had a LoS > 5 days. Using propensity scores for LoS > 5 days, we assembled 2723 pairs of patients with LoS 1-5 vs. > 5 days. The matched cohort of 5446 patients was balanced on 40 baseline characteristics. We repeated the above process in 7045 patients after excluding those with LoS > 10 days, thus assembling a second matched cohort of 2399 pairs of patients with LoS 1-5 vs. 6-10 days. Hazard ratios (HR) and 95% confidence intervals (CI) for outcomes associated with longer LoS were estimated in matched cohorts.

RESULTS

In the primary matched cohort (n = 5446), LoS > 5 days was associated with a higher risk of all-cause readmission at 30 days (HR = 1.16; 95% CI: 1.04-1.31; p = 0.010), but not during longer follow-up. A longer LoS was also associated with a higher risk of mortality during 8.8 years of follow-up (HR = 1.13; 95% CI: 1.06-1.21; p < 0.001). LoS had no association with HF readmission. Similar associations were observed among the matched sensitivity cohort (n = 4798) that excluded patients with LoS > 10 days.

CONCLUSIONS

In propensity score-matched balanced cohorts of patients with HF, a longer LoS was independently associated with poor outcomes, which persisted when LoS > 10 days were excluded.

Digoxin use and lower risk of 30-day all-cause readmission in older patients with heart failure and reduced ejection fraction receiving β-blockers

BACKGROUND

Digoxin use has been associated with a lower risk of 30-day all-cause admission and readmission in patients with heart failure and reduced ejection fraction (HFrEF).

HYPOTHESIS

Digoxin use will be associated with improved outcomes in patients with HFrEF receiving β-blockers.

METHODS

Of the 3076 hospitalized Medicare beneficiaries with HFrEF (EF <45%), 1046 received a discharge prescription for β-blockers, of which 634 were not on digoxin. Of the 634, 204 received a new discharge prescription for digoxin. Propensity scores for digoxin use, estimated for each of the 634 patients, were used to assemble a matched cohort of 167 pairs of patients receiving and not receiving digoxin, balanced on 30 baseline characteristics. Matched patients (n = 334) had a mean age of 74 years and were 46% female and 30% African American.

RESULTS

30-day all-cause readmission occurred in 15% and 27% of those receiving and not receiving digoxin, respectively (hazard ratio [HR]: 0.51, 95% confidence interval [CI]: 0.31-0.83, P = 0.007). This beneficial association persisted during 4 years of follow-up (HR: 0.72, 95% CI: 0.57-0.92, P = 0.008). Digoxin use was also associated with a lower risk of the combined endpoint of all-cause readmission or all-cause mortality at 30 days (HR: 0.54, 95% CI: 0.34-0.86, P = 0.009) and at 4 years (HR: 0.76, 95% CI: 0.61-0.96, P = 0.020).

CONCLUSIONS

In hospitalized patients with HFrEF receiving β-blockers, digoxin use was associated with a lower risk of 30-day all-cause readmission but not mortality, which persisted during longer follow-up.

Digoxin and 30-Day All-Cause Readmission in Long-Term Care Residents Hospitalized for Heart Failure

BACKGROUND

Digoxin use has been shown to be associated with a lower risk of 30-day all-cause hospital readmissions in older patients with heart failure (HF). In the current study, we examined this association among long-term care (LTC) residents hospitalized for HF.

METHODS

Of the 8049 Medicare beneficiaries discharged alive after hospitalization for HF from 106 Alabama hospitals, 545 (7%) were LTC residents, of which 227 (42%) received discharge prescriptions for digoxin. Propensity scores for digoxin use, estimated for each of the 545 patients, were used to assemble a matched cohort of 158 pairs of patients receiving and not receiving digoxin who were balanced on 29 baseline characteristics. Hazard ratios (HRs) and 95% confidence intervals (CIs) for outcomes associated with digoxin among matched patients were estimated using Cox regression models.

RESULTS

Matched patients (n = 316) had a mean age of 83 years, 74% were women, and 18% African American. Thirty-day all-cause readmission occurred in 21% and 20% of patients receiving and not receiving digoxin, respectively (HR, 1.02; 95% CI, 0.63-1.66). Digoxin had no association with all-cause mortality (HR, 0.90; 95% CI, 0.48-1.70), HF readmission (HR, 0.90; 95% CI, 0.38-2.12), or a combined endpoint of all-cause readmission or all-cause mortality (HR, 0.97; 95% CI, 0.65-1.45) at 30 days. These associations remained unchanged at 1 year postdischarge.

CONCLUSIONS

The lack of an association between digoxin and 30-day all-cause readmission in older nursing home residents hospitalized for HF is intriguing and needs to be interpreted with caution given the small sample size.

Exercise capacity and progression from prehypertension to hypertension

Prehypertension is likely to progress to hypertension. The rate of progression is determined mostly by age and resting blood pressure but may also be attenuated by increased fitness. A graded exercise test was performed in 2303 men with prehypertension at the Veterans Affairs Medical Centers in Washington, DC. Four fitness categories were defined, based on peak metabolic equivalents (METs) achieved. We assessed the association between exercise capacity and rate of progression to hypertension (HTN). The median follow-up period was 7.8 years (mean (± SD) 9.2±6.1 years). The incidence rate of progression from prehypertension to hypertension was 34.4 per 1000 person-years. Exercise capacity was a strong and independent predictor of the rate of progression. Compared to the High-Fit individuals (>10.0 METs), the adjusted risk for developing HTN was 66% higher (hazard ratio, 1.66; 95% CI, 1.2 to 2.2; P=0.001) for the Low-Fit and, similarly, 72% higher (hazard ratio, 1.72; 95% CI, 1.2 to 2.3; P=0.001) for the Least-Fit individuals, whereas it was only 36% for the Moderate-Fit (hazard ratio, 1.36; 95% CI, 0.99 to 1.80; P=0.056). Significant predictors for the progression to HTN were also age (19% per 10 years), resting systolic blood pressure (16% per 10 mm Hg), body mass index (15.3% per 5 U), and type 2 diabetes mellitus (2-fold). In conclusion, an inverse, S-shaped association was shown between exercise capacity and the rate of progression from prehypertension to hypertension in middle-aged and older male veterans. The protective effects of fitness were evident when exercise capacity exceeded 8.5 METs. These findings emphasize the importance of fitness in the prevention of hypertension.