Long-term cardiovascular disease outcomes in non-hospitalized medicare beneficiaries diagnosed with COVID-19: Population-based matched cohort study.

BACKGROUND: SARS-CoV2, the virus that causes coronavirus disease 2019 (COVID-19), can affect multiple human organs structurally and functionally, including the cardiovascular system and brain. Many studies focused on the acute effects of COVID-19 on risk of cardiovascular disease (CVD) and stroke especially among hospitalized patients with limited follow-up time. This study examined long-term mortality, hospitalization, CVD and stroke outcomes after non-hospitalized COVID-19 among Medicare fee-for-service (FFS) beneficiaries in the United States. METHODS: This retrospective matched cohort study included 944,371 FFS beneficiaries aged ≥66 years diagnosed with non-hospitalized COVID-19 from April 1, 2020, to April 30, 2021, and followed-up to May 31, 2022, and 944,371 propensity score matched FFS beneficiaries without COVID-19. Primary outcomes were all-cause mortality, hospitalization, and incidence of 15 CVD and stroke. Because most outcomes violated the proportional hazards assumption, we used restricted cubic splines to model non-proportional hazards in Cox models and presented time-varying hazard ratios (HRs) and Bonferroni corrected 95% confidence intervals (CI). RESULTS: The mean age was 75.3 years; 58.0% women and 82.6% non-Hispanic White. The median follow-up was 18.5 months (interquartile range 16.5 to 20.5). COVID-19 showed initial stronger effects on all-cause mortality, hospitalization and 12 incident CVD outcomes with adjusted HRs in 0-3 months ranging from 1.05 (95% CI 1.01-1.09) for mortality to 2.55 (2.26-2.87) for pulmonary embolism. The effects of COVID-19 on outcomes reduced significantly after 3-month follow-up. Risk of mortality, acute myocardial infarction, cardiomyopathy, deep vein thrombosis, and pulmonary embolism returned to baseline after 6-month follow-up. Patterns of initial stronger effects of COVID-19 were largely consistent across age groups, sex, and race/ethnicity. CONCLUSIONS: Our results showed a consistent time-varying effects of COVID-19 on mortality, hospitalization, and incident CVD among non-hospitalized COVID-19 survivors.

County-Level Cardiac Rehabilitation and Broadband Availability: Opportunities for Hybrid Care in the United States.

PURPOSE: Cardiac rehabilitation (CR) improves patient outcomes and quality of life and can be provided virtually through hybrid CR. However, little is known about CR availability in conjunction with broadband access, a requirement for hybrid CR. This study examined the intersection of CR and broadband availability at the county level, nationwide. METHODS: Data were gathered and analyzed in 2022 from the 2019 American Community Survey, the Centers for Medicare & Medicaid Services, and the Federal Communications Commission. Spatially adaptive floating catchments were used to calculate county-level percent CR availability among Medicare fee-for-service beneficiaries. Counties were categorized: by CR availability, whether lowest (ie, CR deserts), medium, or highest; and by broadband availability, whether CR deserts with majority-available broadband, or dual deserts. Results were stratified by state. County-level characteristics were examined for statistical significance by CR availability category. RESULTS: Almost half of US adults (n = 116 325 976, 47.2%) lived in CR desert counties (1691 counties). Among adults in CR desert counties, 96.8% were in CR deserts with majority-available broadband (112 626 906). By state, the percentage of the adult population living in CR desert counties ranged from 3.2% (New Hampshire) to 100% (Hawaii and Washington, DC). Statistically significant differences in county CR availability existed by race/ethnicity, education, and income. CONCLUSIONS: Almost half of US adults live in CR deserts. Given that up to 97% of adults living in CR deserts may have broadband access, implementation of hybrid CR programs that include a telehealth component could expand CR availability to as many as 113 million US adults.

Bystander CPR and Long-Term Survival in Older Adults With Out-of-Hospital Cardiac Arrest.

BACKGROUND: Most studies on bystander cardiopulmonary resuscitation (CPR) for out-of-hospital cardiac arrest (OHCA) have focused on in-hospital or short-term survival. OBJECTIVES: The purpose of this study was to examine the association between bystander CPR and long-term survival outcomes for OHCA. METHODS: Within the Cardiac Arrest Registry to Enhance Survival, we identified 152,653 patients with OHCA ≥65 years of age or older. Using multivariable hierarchical logistic regression, we first examined the association between bystander CPR and in-hospital survival. Then, among those surviving to discharge and linked to Medicare files, we evaluated the association between bystander CPR and long-term mortality over 5 years using multivariable Cox regression. RESULTS: Overall, 58,464 (38.3%) received bystander CPR. Patients receiving bystander CPR were more likely to have an OHCA that was witnessed, in a public location, and with an initial shockable rhythm. Bystander CPR was associated with a 24% higher likelihood of surviving to hospital discharge (10.2% vs 5.5%; adjusted relative risk: 1.24 [95% CI: 1.19-1.29]; P < 0.001), and this survival benefit was similar (interaction P = 0.24) for those who were 65 to 74, 75 to 84, and ≥85 years of age. Among patients surviving to hospital discharge (median follow-up of 31 months), bystander CPR was additionally associated with lower long-term mortality vs those without bystander CPR (adjusted hazard ratio: 0.78 [95% CI: 0.73-0.84]; P < 0.001), and this benefit was also consistent across age groups (interaction P = 0.13). CONCLUSIONS: In older adults with OHCA, bystander CPR was associated with higher rates of in-hospital survival. This survival benefit was not attenuated by competing mortality risks but increased in magnitude after hospital discharge.

Long-Term Outcomes for Out-of-Hospital Cardiac Arrest in Elderly Patients: An Analysis of Cardiac Arrest Registry to Enhance Survival Data Linked to Medicare Files.

BACKGROUND: Most studies on out-of-hospital cardiac arrest have primarily focused on in-hospital or short-term survival. Little is known about long-term outcomes and resource use among survivors of out-of-hospital cardiac arrest. METHODS: In this observationsl study, we describe overall long-term outcomes for patients from the national Cardiac Arrest Registry to Enhance Survival linked to Medicare files to create the Cardiac Arrest Registry to Enhance Survival: Mortality, Events, and Costs for Cardiac Arrest survivors dataset. Cardiac Arrest Registry to Enhance Survival data between 2013 and 2019 were linked to Medicare data using probabilistic matching algorithms. Overall long-term mortality, readmissions, and index hospitalization costs are reported for the overall cohort. RESULTS: Among 56 425 patients who were 65 years of age or older in Cardiac Arrest Registry to Enhance Survival who survived to hospital admission, 26 875 (47.6%) were successfully linked to Medicare files. Mean (+SD) cost of the index hospitalization was $23 262+$24 199 and the median cost was $14 636 (interquartile range, $9930-$30 033). Overall, 8676 (32.3%) survived to hospital discharge with 38.0% discharged home, 11.8% to hospice care, and the remaining 50.2% to other inpatient, skilled nursing care, or rehabilitation facilities. Mortality after discharge was initially high (27.0% at 3 months) and then increased gradually, with 1- and 3-year mortality of 37.1% and 50.1%, respectively. During the first year, 40.1% were readmitted at least once, with 19.7% readmitted on > 1 occasion. CONCLUSIONS: The Cardiac Arrest Registry to Enhance Survival: Mortality, Events, and Costs for Cardiac Arrest survivors registry includes rich data on postdischarge outcomes and resource utilization. Use of this dataset will enable future investigations on the long-term effectiveness, costs, and cost-effectiveness of various interventions for out-of-hospital cardiac arrest in elderly patients.

Race and ethnicity data in the cardiac arrest registry to enhance survival: Insights from medicare self-reported data.

BACKGROUND: For out-of-hospital cardiac arrest (OHCA), assignment of race/ethnicity data can be challenging. Validation of race/ethnicity in registry data with patients' self-reported race/ethnicity would provide insights regarding misclassification. METHODS: Using recently linked 2013-2019 Cardiac Arrest Registry to Enhance Survival (CARES) data with Medicare files, we examined the concordance of race/ethnicity in CARES with self-reported race/ethnicity in Medicare. Among patients with unknown race/ethnicity in CARES, race/ethnicity data from Medicare files were reported. RESULTS: Of 26,875 patients in the linked data, 5757 (21.4%) had unknown race/ethnicity in CARES. Of the remaining 21,118 patients, 14,284 (67.6%) were identified in CARES as non-Hispanic White, 4771 (22.6%) as non-Hispanic Black, 1213 (5.7%) as Hispanic, 760 (3.6%) as Asian or Pacific Islander, and 90 (0.4%) as American Indian or Alaskan Native. The concordance rate for race/ethnicity between CARES and Medicare was 93.4% for patients reported as non-Hispanic White in CARES, 89.1% for non-Hispanic Blacks, 74.6% for Hispanics, 69.6% for Asians and Pacific Islanders, and 37.8% for American Indian or Alaskan Natives. For the 5757 patients with unknown race/ethnicity in CARES, 3973 (69.0%) self-reported in Medicare as non-Hispanic White, 617 (10.7%) as non-Hispanic Black, 425 (7.4%) as Hispanic, 491 (8.5%) as Asian or Pacific Islander, and 52 (0.9%) as American Indian or Alaskan Native. Race/ethnicity remained unknown in 199 (3.5%) of patients. CONCLUSION: Race/ethnicity in CARES was highly concordant with self-reported race/ethnicity in Medicare, especially for non-Hispanic White and Black individuals. For patients with unknown race/ethnicity data in CARES, the vast majority were of White race.

Antihypertensive and Statin Medication Adherence Among Medicare Beneficiaries.

INTRODUCTION: Medication adherence is important for optimal management of chronic conditions, including hypertension and hypercholesterolemia. This study describes adherence to antihypertensive and statin medications, individually and collectively, and examines variation in adherence by demographic and geographic characteristics. METHODS: The 2017 prescription drug event data for beneficiaries with Medicare Part D coverage were assessed. Beneficiaries with a proportion of days covered ≥80% were considered adherent. Adjusted prevalence ratios were estimated to quantify the associations between demographic and geographic characteristics and adherence. Adherence estimates were mapped by county of residence using a spatial empirical Bayesian smoothing technique to enhance stability. Analyses were conducted in 2019‒2021. RESULTS: Among the 22.5 million beneficiaries prescribed antihypertensive medications, 77.1% were adherent; among the 16.1 million prescribed statin medications, 81.9% were adherent; and among the 13.5 million prescribed antihypertensive and statin medications, 70.3% were adherent to both. Adherence varied by race/ethnicity: American Indian/Alaska Native (adjusted prevalence ratio=0.83, 95% confidence limit=0.82, 0.842), Hispanic (adjusted prevalence ratio=0.90, 95% confidence limit=0.90, 0.91), and non-Hispanic Black (adjusted prevalence ratio=0.87, 95% confidence limit=0.86, 0.87) beneficiaries were less likely to be adherent than non-Hispanic White beneficiaries. County-level adherence ranged across the U.S. from 25.7% to 88.5% for antihypertensive medications, from 36.0% to 93.8% for statin medications, and from 20.8% to 92.9% for both medications combined and tended to be the lowest in the southern U.S. CONCLUSIONS: This study highlights opportunities for efforts to remove barriers and support medication adherence, especially among racial/ethnic minority groups and within the regions at greatest risk for adverse cardiovascular outcomes.

Tracking Cardiac Rehabilitation Utilization in Medicare Beneficiaries: 2017 UPDATE.

PURPOSE: This study updates cardiac rehabilitation (CR) utilization data in a cohort of Medicare beneficiaries hospitalized for CR-eligible events in 2017, including stratification by select patient demographics and state of residence. METHODS: We identified Medicare fee-for-service beneficiaries who experienced a CR-eligible event and assessed their CR participation (≥1 CR sessions in 365 d), engagement, and completion (≥36 sessions) rates through September 7, 2019. Measures were assessed overall, by beneficiary characteristics and state of residence, and by primary (myocardial infarction; coronary artery bypass surgery; heart valve repair/replacement; percutaneous coronary intervention; or heart/heart-lung transplant) and secondary (angina; heart failure) qualifying event type. RESULTS: In 2017, 412 080 Medicare beneficiaries had a primary CR-eligible event and 28.6% completed ≥1 session of CR within 365 d after discharge from a qualifying event. Among beneficiaries who completed ≥1 CR session, the mean total number of sessions was 25 ± 12 and 27.6% completed ≥36 sessions. Nebraska had the highest enrollment rate (56.1%), with four other states also achieving an enrollment rate >50% and 23 states falling below the overall rate for the United States. CONCLUSIONS: The absolute enrollment, engagement, and program completion rates remain low among Medicare beneficiaries, indicating that many patients did not benefit or fully benefit from a class I guideline-recommended therapy. Additional research and continued widespread adoption of successful enrollment and engagement initiatives are needed, especially among identified populations.

COVID-19 and Risk of Acute Ischemic Stroke Among Medicare Beneficiaries Aged 65 Years or Older: Self-Controlled Case Series Study.

BACKGROUND AND OBJECTIVES: Findings of association between coronavirus disease 2019 (COVID-19) and stroke remain inconsistent, ranging from significant association to absence of association to less than expected ischemic stroke among hospitalized patients with COVID-19. The current study examined the association between COVID-19 and risk of acute ischemic stroke (AIS). METHODS: We included 37,379 Medicare fee-for-service (FFS) beneficiaries aged ≥65 years diagnosed with COVID-19 from April 1, 2020, through February 28, 2021, and AIS hospitalization from January 1, 2019, through February 28, 2021. We used a self-controlled case series design to examine the association between COVID-19 and AIS and estimated the incidence rate ratios (IRRs) by comparing incidence of AIS in risk periods (0-3, 4-7, 8-14, 15-28 days after diagnosis of COVID-19) vs control periods. RESULTS: Among 37,379 Medicare FFS beneficiaries with COVID-19 and AIS, the median age at diagnosis of COVID-19 was 80.4 (interquartile range 73.5-87.1) years and 56.7% were women. When AIS at day of exposure (day = 0) was included in the risk periods, IRRs at 0-3, 4-7, 8-14, and 15-28 days following COVID-19 diagnosis were 10.3 (95% confidence interval 9.86-10.8), 1.61 (1.44-1.80), 1.44 (1.32-1.57), and 1.09 (1.02-1.18); when AIS at day 0 was excluded in the risk periods, the corresponding IRRs were 1.77 (1.57-2.01) (day 1-3), 1.60 (1.43-1.79), 1.43 (1.31-1.56), and 1.09 (1.01-1.17), respectively. The association appeared to be stronger among younger beneficiaries and among beneficiaries without prior history of stroke but largely consistent across sex and race/ethnicities. DISCUSSION: Risk of AIS among Medicare FFS beneficiaries was 10 times (day 0 cases in the risk period) as high during the first 3 days after diagnosis of COVID-19 as during the control period and the risk associated with COVID-19 appeared to be stronger among those aged 65-74 years and those without prior history of stroke. CLASSIFICATION OF EVIDENCE: This study provides Class IV evidence that severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is associated with increased risk of AIS in the first 3 days after diagnosis in Medicare FFS beneficiaries ≥65 years of age.

Herpes Zoster Vaccine Live and Risk of Stroke Among Medicare Beneficiaries: A Population-Based Cohort Study.

Background and Purpose: Herpes zoster (HZ) is associated with increased risk of stroke, and zoster vaccine live (ZVL, Zostavax) reduces the risk of HZ. No study has examined the association between ZVL (Zostavax) and risk of stroke. Present study examined association between receipt of ZVL (Zostavax) and risk of stroke among older US population. Methods: Our study included 1 603 406 US Medicare fee-for-service beneficiaries aged ≥66 years without a history of stroke and who received ZVL (Zostavax) during 2008 to 2014, and 1 603 406 propensity score-matched unvaccinated beneficiaries followed through to December 31, 2017. We used Cox proportional hazard models to examine association between ZVL (Zostavax) and composite fatal or nonfatal incident stroke outcomes. Results: During a median of 5.1 years follow-up (interquartile range, 3.9­6.7), we documented 64 635 stroke events, including 43 954 acute ischemic strokes and 6727 hemorrhagic strokes, among vaccinated beneficiaries during 8 755 331 person-years. The corresponding numbers among unvaccinated beneficiaries were 73 023, 50 476, and 7276, respectively, during 8 517 322 person-years. Incidence comparing vaccinated to unvaccinated beneficiaries were 7.38 versus 8.57 per 1000 person-years for all stroke, 5.00 versus 5.90 for acute ischemic stroke, and 0.76 versus 0.84 for hemorrhagic stroke (P<0.001 for all difference). Adjusted hazard ratios comparing vaccinated to unvaccinated beneficiaries were 0.84 (95% CI, 0.83­0.85), 0.83 (0.82­0.84), and 0.88 (0.85­0.91) for all stroke, acute ischemic stroke, and hemorrhagic stroke, respectively. The association between ZVL (Zostavax) and risk of stroke appeared to be stronger among younger beneficiaries, beneficiaries who did not take antihypertensive or statin medications and who had fewer comorbid conditions (P<0.05 for interaction) but largely consistent across sex, low-income status, and racial groups. Conclusions: Among Medicare fee-for-service beneficiaries, receipt of ZVL (Zostavax) was associated with lower incidence of stroke. Our findings may encourage people to get vaccinated against HZ to reduce HZ and HZ-associated stroke risk.

Effect of herpes zoster vaccine and antiviral treatment on risk of ischemic stroke.

OBJECTIVE: To determine whether increased risk of acute ischemic stroke (AIS) following herpes zoster (HZ) might be modified by the status of zoster vaccine live (ZVL) vaccination and antiviral treatment following HZ. METHODS: We included 87,405 Medicare fee-for-service beneficiaries aged ≥66 years diagnosed with HZ and AIS from 2008 to 2017. We used a self-controlled case series design to examine the association between HZ and AIS, and estimated incidence rate ratios (IRRs) by comparing incidence of AIS in risk periods vs control periods. To examine effect modification by ZVL and antiviral treatment, beneficiaries were classified into 4 mutually exclusive groups: (1) no vaccination and no antiviral treatment; (2) vaccination only; (3) antiviral treatment only; and (4) both vaccination and antiviral treatment. We tested for interaction to examine changes in IRRs across 4 groups. RESULTS: Among 87,405 beneficiaries with HZ and AIS, 22.0%, 2.0%, 70.1%, and 5.8% were in groups 1 to 4, respectively. IRRs in 0-14, 15-30, 31-90, and 91-180 days following HZ were 1.89 (95% confidence interval [CI], 1.77-2.02), 1.58 (95% CI, 1.47-1.69), 1.36 (95% CI, 1.31-1.42), and 1.19 (95% CI, 1.15-1.23), respectively. There was no evidence of effect modification by ZVL and antiviral treatment on AIS (p = 0.067 for interaction). The pattern of association between HZ and risk for AIS was largely consistent across age group, sex, and race. CONCLUSIONS: Risk of AIS increased significantly following HZ, and this increased risk was not modified by ZVL and antiviral treatment. Our findings suggest the importance of following recommended HZ vaccination in prevention of HZ and HZ-associated AIS.

National Rates of Nonadherence to Antihypertensive Medications Among Insured Adults With Hypertension, 2015.

Despite the importance of antihypertensive medication therapy for blood pressure control, no single data system provides estimates of medication nonadherence rates across age groups and health insurance plans types. Using multiple administrative datasets and national survey data, we determined health insurance plan-specific and overall weighted national rates of nonadherence to antihypertensive medications among insured hypertensive US adults in 2015. We used 2015 prescription claims data from Medicare Part D and 3 IBM MarketScan databases (Commercial, Medicaid, Medicare Supplemental) to calculate medication nonadherence rates among hypertensive adults aged ≥18 years with public or private health insurance using the proportion of days covered algorithm. These findings, in combination with National Health Interview Survey findings, were used to project national weighted estimates of nonadherence. We included 23.8 million hypertensive adults who filled 265.8 million prescriptions for antihypertensive medications. Nonadherence differed by health insurance plan type (highest for Medicaid members, 55.4%; lowest for Medicare Part D members, 25.2%). The overall weighted national nonadherence rate was 31.0%, with greater nonadherence among women versus men, younger versus older adults (aged 18-34 years, 58.1%; aged 65-74 years, 24.4%), fixed-dose combination medication nonusers (31.2%) versus users (29.4%), and by pharmacy outlet type (retail only, 30.7%; any mail order, 19.8%). In 2015, almost one-third (≈16.3 million) of insured US adults with diagnosed hypertension were considered nonadherent to their antihypertensive medication regimen, and considerable disparities were evident. Public health and healthcare professionals can use available evidence-based interventions to address nonadherence and improve blood pressure control.

Antihypertensive Medication Adherence and Risk of Cardiovascular Disease Among Older Adults: A Population-Based Cohort Study.

BACKGROUND: Antihypertension medication (antihypertensive) adherence lowers risk of cardiovascular disease (CVD); few studies have examined this association among older adults. METHODS AND RESULTS: We assessed this association among Medicare fee-for-service beneficiaries aged 66 to 79 years who were newly diagnosed with hypertension and initiated on antihypertensives in 2008-2009 (n=155 597). We calculated proportion of days covered (PDC) during follow-up, using proportional subdistribution hazard models, to examine association between antihypertensive adherence and a composite CVD outcomes, including first incident of fatal/nonfatal acute myocardial infarction, ischemic heart disease, stroke/transient ischemic attack, and heart failure. During follow-up (median 5.8 years and 798 621 person-years), we documented 47 198 CVD events. Among beneficiaries, 60.8%, 30.3%, and 8.9% had PDC ≥80%, 40% to 79%, and <40%. Crude incidence of CVD events were 40.1 (95% CI, 40.0-40.1), 93.9 (93.8-93.9), and 98.1 (98.1-98.2) per 1000 person-years for PDC ≥80%, 40% to 79%, and <40%, respectively. Adjusted hazard ratios for CVD events were 1.0 (<40% as reference), 1.0 (0.97-1.03) for 40% to 79%, and 0.44 (0.42-0.45) for ≥80% (P<0.001). Dose-response analysis suggested a nonlinear relationship between PDC and risk for CVD events with a protective effect of ≥80%. The pattern of associations between PDC and ischemic heart disease, stroke/transient ischemic attack, and heart failure were largely consistent as for CVD events and across different groups. CONCLUSIONS: Antihypertensive adherence was associated with a significantly lower risk of CVD events among older adults. There appeared to be a threshold effect in reducing CVD events at around PDC 80%, above which the risk for CVD reduced substantially.

Vital Signs: Disparities in Antihypertensive Medication Nonadherence Among Medicare Part D Beneficiaries - United States, 2014.

INTRODUCTION: Nonadherence to taking prescribed antihypertensive medication (antihypertensive) regimens has been identified as a leading cause of poor blood pressure control among persons with hypertension and an important risk factor for adverse cardiovascular disease outcomes. CDC and the Centers for Medicare and Medicaid Services analyzed geographic, racial-ethnic, and other disparities in nonadherence to antihypertensives among Medicare Part D beneficiaries in 2014. METHODS: Antihypertensive nonadherence, defined as a proportion of days a beneficiary was covered with antihypertensives of <80%, was assessed using prescription drug claims data among Medicare Advantage or Medicare fee-for-service beneficiaries aged ≥65 years with Medicare Part D coverage during 2014 (N = 18.5 million). Analyses were stratified by antihypertensive class, beneficiaries' state and county of residence, type of prescription drug plan, and treatment and demographic characteristics. RESULTS: Overall, 26.3% (4.9 million) of Medicare Part D beneficiaries using antihypertensives were nonadherent to their regimen. Nonadherence differed by multiple factors, including medication class (range: 16.9% for angiotensin II receptor blockers to 28.9% for diuretics); race-ethnicity (24.3% for non-Hispanic whites, 26.3% for Asian/Pacific Islanders, 33.8% for Hispanics, 35.7% for blacks, and 38.8% for American Indians/Alaska Natives); and state of residence (range 18.7% for North Dakota to 33.7% for the District of Columbia). Considerable county-level variation in nonadherence was found; the highest nonadherence tended to occur in the southern United States (U.S. Census region nonadherence = 28.9% [South], 26.7% [West], 24.1% [Northeast], and 22.8% [Midwest]) CONCLUSIONS AND IMPLICATIONS FOR PUBLIC HEALTH PRACTICE: More than one in four Medicare Part D beneficiaries using antihypertensives were nonadherent to their regimen, and certain racial/ethnic groups, states, and geographic areas were at increased risk for nonadherence. These findings can help inform focused interventions among these groups, which might improve blood pressure control and cardiovascular disease outcomes.

The influence of deductible health plans on receipt of the human papillomavirus vaccine series.

PURPOSE: To evaluate whether enrollment in deductible health plans (DHP) with higher patient cost-sharing requirements than traditional health maintenance organization plans (HMP) decreased initiation and completion of the human papillomavirus (HPV) vaccine series recommended for prevention of cervical cancer. METHODS: This was a retrospective observational study of 9- to 26-year-old females at Kaiser Permanente Georgia and Kaiser Permanente Colorado who were HPV vaccine naive at time of enrollment in a self-pay DHP or HMP in 2007. Estimates of rates of initiation and completion of the HPV vaccine series from plan enrollment in 2007 through December 2009 were obtained using Cox proportional hazards regressions (accounting for censoring) on samples matched on the propensity to enroll in a DHP versus HMP. RESULTS: Initiation of the HPV vaccine series was 22.2% and 24.4% in the DHP and HMP groups, respectively, at Kaiser Permanente Georgia; completion was 12.3% and 14.4% in the DHP and HMP groups, respectively. Human papillomavirus vaccine series initiation was higher at Kaiser Permanente Colorado, but completion was lower. In the Cox proportional hazards regressions, rates of initiation and completion of the HPV vaccine series did not differ significantly (p ≤ .05) by plan type (DHP vs. HMP) at both sites. The primary care visit rate included in these regressions had a significant, positive association with initiation and completion of the HPV vaccine series. CONCLUSIONS: Enrollment in a DHP versus an HMP did not directly affect initiation or completion of the HPV vaccine series among age-eligible females. Independent of plan type, more frequent primary care visits increased initiation and completion rates.