About

Zach Marcum is an Affiliate Associate Professor and Principal at Medicus Economics, LLC, affiliated with the Department of Pharmacy at the University of Washington. He holds a Doctor of Pharmacy (PharmD) degree from Butler University and a Doctor of Philosophy (PhD) in Clinical & Translational Science from the University of Pittsburgh School of Medicine. Additionally, he earned a Master of Science (MS) in Clinical Research from the University of Pittsburgh. His research focus involves clinical and translational science, with particular expertise in health economics, outcomes research, and pharmacoeconomics. As a faculty member, he contributes to the advancement of pharmacy practice and health outcomes through his academic and professional activities.

Research topics

• Medicine
• Internal medicine
• Psychiatry
• Gerontology
• Psychology
• Endocrinology
• Physical therapy
• Family medicine
• Emergency medicine

Selected publications

• Angiotensin II–Stimulating Antihypertensive Medications and Dementia-Related Neuropathology

  JAMA Network Open · 2026-02-11 · 2 citations

  articleOpen access

  Importance: Antihypertensive medications that stimulate angiotensin II type 2 or 4 receptors (angiotensin II-stimulating medications) may be associated with lower risk of dementia. Objective: To examine associations between cumulative exposure to angiotensin II-stimulating vs angiotensin II-inhibiting antihypertensive medications and neuropathology, accounting for blood pressure. Design, Setting, and Participants: This community-based autopsy cohort study from the Adult Changes in Thought cohort was conducted at Kaiser Permanente Washington between February 24, 1994, and November 25, 2022, among 756 participants who had blood pressure measurements and at least 1 person-year (PY) of angiotensin II-stimulating or -inhibiting antihypertensive medication exposure prior to death. Statistical analysis was performed between September 2024 and August 2025. Exposure: Angiotensin II-stimulating antihypertensive medications (angiotensin II receptor blockers, dihydropyridine calcium channel blockers, thiazides) and angiotensin II-inhibiting antihypertensive medications (angiotensin-converting enzyme inhibitors, β-blockers, nondihydropyridine calcium channel blockers) were ascertained from paper-based medical records (before 1977) and electronic prescription fill data (after 1977). The primary exposure was cumulative angiotensin II PYs, and the secondary exposure was long-term use (≥15 years). Main Outcomes and Measures: Neuropathology outcomes were classified as Alzheimer disease related, vascular brain injury, or other. Exploratory outcomes included quantitative measures of Aβ42 and phosphorylated tau. Data were analyzed using multivariable modified Poisson, proportional odds, and linear regression models and accounted for potential selection bias. Results: The sample included 756 participants (mean [SD] age at death, 89.2 [6.4] years; 440 women [58.2%]; mean [SD] follow-up, 22.2 [13.5] years). Compared with exposure to 5 additional PYs of angiotensin II-inhibiting antihypertensive medications, exposure to 5 additional PYs of angiotensin II-stimulating antihypertensive medications was associated with a 6% lower risk for arteriolosclerosis (relative risk [RR], 0.94; 95% CI, 0.89-0.99), with long-term use associated with a 24% lower risk (RR, 0.76; 95% CI, 0.63-0.91). For exploratory outcomes, PYs of angiotensin II-stimulating antihypertensive medications were associated with less quantitative phosphorylated tau burden in several brain regions (temporal lobe [adjusted ratio of geometric means, 0.79; 95% CI, 0.62-1.00], hippocampus [adjusted ratio of geometric means, 0.83; 95% CI, 0.71-0.97], cornu ammonis subfield 1 [adjusted ratio of geometric means, 0.86; 95% CI, 0.74-0.99], and transentorhinal cortex [adjusted ratio of geometric means, 0.83; 95% CI, 0.70-0.98]) but not with Aβ42 quantitative measures. Conclusions and Relevance: In this community-based autopsy cohort study, angiotensin II-stimulating antihypertensive medications were associated with lower risk of neuropathological burden, supporting findings from epidemiologic dementia studies. Additional mechanistic research examining the effects of individual antihypertensive classes on Alzheimer disease-related biomarkers is warranted.

  PublisherOA PDFDOI

• Clinical and economic burden of chronic kidney disease in Medicare Fee-for-Service beneficiaries with and without comorbid type 2 diabetes and heart failure: A retrospective cohort study

  Journal of Managed Care & Specialty Pharmacy · 2025-12-04

  article

  BACKGROUND: Chronic kidney disease (CKD) is common in older adults and is often associated with type 2 diabetes (T2DM) and heart failure (HF). However, little is known about the burden of newly diagnosed CKD in Medicare Fee-for-Service (FFS) beneficiaries, including those with comorbid T2DM or HF. OBJECTIVE: To quantify the clinical and economic burden of CKD in Medicare FFS beneficiaries, including those with comorbid T2DM or HF. METHODS: In this retrospective cohort study using 100% Medicare FFS claims data (Parts A, B, D) from 2014 to 2022, beneficiaries with incident CKD (based on a diagnosis code on 2 distinct dates) from January 1, 2015, to December 31, 2021, were included; index date was the date of earliest CKD diagnosis. Beneficiaries with a diagnosis of CKD, acute kidney injury, dialysis, kidney transplantation, or a claim for any condition other than T2DM that could cause kidney disease during a 365-day baseline period prior to index date were excluded. Beneficiaries with CKD were categorized into 4 mutually exclusive cohorts: CKD-only; CKD+HF; CKD+T2DM; and CKD+HF+T2DM based on claims during the baseline period. Clinical burden was measured as prevalence at baseline and incidence of key clinical outcomes at 12 months of follow-up. Economic burden was measured as all-cause and CKD-related health care resource utilization (HCRU) and inflation-adjusted costs in the baseline period and at 12 months of follow-up. RESULTS: < 0.001 for comparison across cohorts). Relative spending across cohorts was similar for CKD-related total costs at 12 months. CONCLUSIONS: Older adults with a new diagnosis of CKD experienced considerable clinical and economic burden, and presence of T2DM and HF was associated with larger burden. All-cause mean total costs at 12 months after a new diagnosis of CKD ranged from $24,180 for the CKD-only cohort to $54,477 for the CKD+HF+T2DM cohort.

  PublisherDOI

• EE478 Foregone Net Monetary Benefit From Underdiagnosis and Undertreatment of Mild Cognitive Impairment Due to Alzheimer’s Disease in the Medicare Population

  Value in Health · 2025-12-01

  article
  PublisherDOI

• Cumulative Anticholinergic Exposure and Change in Gait Speed and Grip Strength in Older Adults

  JAMA Network Open · 2025-07-10 · 2 citations

  articleOpen access

  Importance: Anticholinergics have been associated with functional decline in older adults. Past studies have assumed constant effects over time and have not considered the etiologically relevant exposure window. Objective: To examine the association of anticholinergic exposure with gait speed and grip strength assuming constant and time-varying effects of daily exposure. Design, Setting, and Participants: This cohort study used data collected from February 1994 to March 2020 in the Adult Changes in Thought study at Kaiser Permanente Washington, an integrated health care delivery organization. Participants with at least 2 study visits and at least 10 years of enrollment prior to index were included. Data were analyzed from January 2023 to December 2024. Exposure: Conventional anticholinergic exposures (10-year total standardized daily dose [TSDD] and 2-year mean SDD [mSDD]) assumed constant daily exposure effects. Weighted cumulative exposures (WCE) explored different exposure windows (T = 2, 4, 6, 8, or 10 years) and were quantified as T-year weighted mSDD to allow for time-varying effects of daily exposure. Main Outcomes and Measures: Adjusted linear models with generalized estimating equations estimated mean differences (MDs) in change rates in gait speed or grip strength between anticholinergic TSDD and mSDD categories and per unit increase in weighted mSDD. Model fits were assessed by quasi-information criterion (QIC). Results: The total sample included 4283 participants, with 4210 participants (2468 women [58.6%]; mean [SD] age,74.3 [6.1] years) with 8.2 (5.4) years of follow-up in the gait speed sample, and 4200 participants (2458 [58.5%] women, mean [SD] age 74.5 [6.1]) in the grip strength sample. Compared with nonusers, a greater decline rate in gait speed was found for those with 10-year TSDD 1096 or greater (MD per year, -0.0132 [95% CI, -0.0193 to -0.0070] m/s) and for 2-year mSDD 0.5 or greater (MD per year, -0.0101 [95% CI, -0.0174 to -0.0029] m/s). The 4-year WCE model had the lowest QIC and showed a significantly greater decline rate per 1-unit increase in weighted mSDD (MD per year, -0.0034 [95% CI -0.0048 to -0.0019] m/s). There were no significant associations between conventional exposures and grip strength, but the 6-year WCE model had the lowest QIC (MD per year, -0.0329 [95% CI -0.0612 to -0.0046] kg). Conclusions and Relevance: Is this cohort study, higher anticholinergic exposure was associated with accelerated decline in physical performance, consistent with clinically meaningful decline. These findings suggest that minimizing anticholinergic medications is important for healthy aging.

  PublisherOA PDFDOI

• Brain metastases and mortality in patients with ALK + metastatic non-small cell lung cancer treated with second-generation ALK tyrosine kinase inhibitors as first-line targeted therapies: An observational cohort study

  Lung Cancer · 2025-02-04 · 5 citations

  articleOpen access

  BACKGROUND: Brain metastases (BM) are common in patients with ALK + metastatic non-small cell lung cancer (mNSCLC). Limited contemporary real-world evidence exists on the burden of BM in these patients. This study estimated the cumulative incidence of BM in patients with ALK + mNSCLC treated with second-generation ALK tyrosine kinase inhibitors (TKI) as first-line (1L) targeted therapies and assessed the association between BM and mortality. MATERIALS AND METHODS: Using a 100 % sample of Medicare fee-for-service and Advantage beneficiaries from 2017 to 2022, patients > 65 years with ALK + mNSCLC (index date = 1L alectinib/brigatinib following lung cancer diagnosis) were identified. The cumulative incidence of BM was calculated, accounting for competing risk of death, overall and by age and race/ethnicity. To assess the association between BM and death, a time-varying Cox proportional hazards model compared the risk of death in those with incident, and baseline BM, separately, to those without BM, adjusting for confounders. RESULTS: In 1040 patients, 289 (28 %) had baseline BM. In 751 patients without baseline BM, the cumulative incidence of BM was 20 % after 5 years. After 4 years, the cumulative incidence of BM was highest in patients ≥ 85 years (25 %) and in non-White patients (23 %). Patients with incident BM had 2.6 times the risk of mortality compared to patients without BM (hazard ratio (HR): 2.59, 95 % confidence interval (CI): 1.98-3.38), while patients with baseline BM had 1.5 times the risk of mortality compared to patients without BM (HR: 1.46, 95 % CI: 1.20-1.77). CONCLUSIONS: Patients with ALK + mNSCLC treated with second-generation ALK TKIs as 1L targeted therapies faced a high burden of BM. Incident BM were associated with increased mortality risk to a greater extent than baseline BM. Efforts are needed to provide safe and efficacious approaches to prevention and treatment of BM, including additional monitoring as required, in patients with ALK + mNSCLC.

  PublisherOA PDFDOI

• Associations of Pain Characteristics With Physical Capacity Trajectories Among Older Adults in the United States

  Clinical Journal of Pain · 2025-05-29 · 1 citations

  articleOpen access

  OBJECTIVE: To investigate the associations of pain characteristics with trajectories of physical capacity in older adults and determined if bothersome and activity-limiting pain modified the association between the number of chronic conditions and trajectories of physical capacity. METHODS: We performed a cohort study with 6783 community-dwelling adults ≥65 years old who participated in the National Health and Aging Trends Study from 2011 to 2016. We assessed baseline pain characteristics and the number of self-reported chronic conditions (0 to 12) at baseline. Longitudinal physical capacity outcomes were categorized using previously identified performance-based and self-reported trajectory groups from this cohort. Multinomial logistic regression examined associations of pain characteristics with trajectories of physical capacity, adjusting for demographic and health characteristics. We then tested for effect modification using an interaction term in regression models. RESULTS: Participants who reported bothersome pain, activity-limiting pain, greater number of pain sites, and more frequent pain medication use at baseline were significantly more likely to demonstrate either "consistently very low" or declining physical capacity trajectories compared with a "consistently high" trajectory. The negative impact of chronic disease burden on risk of a declining trajectory for both performance-based and self-reported physical capacity was greater in those with bothersome pain versus those not reporting pain. DISCUSSION: Overall, we found bothersome pain and other pain characteristics were significantly associated with poor and worsening trajectories of physical capacity in older adults. This suggests pain is an important prognostic factor for targeting population-level interventions addressing physical capacity.

  PublisherOA PDFDOI

• Initiation of ARB- vs ACEI-Based Antihypertensive Medication Regimens and Differences in Rates of Cognitive Decline

  Neurology Open Access · 2025-06-06 · 1 citations

  articleOpen access

  An Analysis of SPRINT" by Andrews et al., 1 in Table 2, the difference in mean slopes for Montreal Cognitive Assessment (0-30) should be "0.06 (-0.01 to 0.12)."The corrected Table 2 follows.The authors regret the error.

  PublisherDOI

• P18 Disparities in Antipsychotic Prescribing Among the US Medicare Population

  Value in Health · 2025-07-01

  article
  PublisherDOI

• 0636 Estimating Underdiagnosis of Obstructive Sleep Apnea in Medicare Claims Data

  SLEEP · 2025-05-01

  articleOpen access1st authorCorresponding

  Abstract Introduction Claims-based measurement often underestimates the prevalence of chronic diseases, such as obstructive sleep apnea (OSA), due to the underreporting of diagnosis codes on billing records. Despite this limitation, claims data remain a valuable source for understanding disease burden due to their large sample sizes and patient-level, longitudinal follow-up capabilities. To address the underestimation of chronic disease prevalence in claims data, a mathematical framework can be applied to leverage the longitudinal diagnosis information and adjust the estimates for undiagnosed cases. Methods We applied the method described by Stocking et al (2023), which identifies latent individuals—those likely to have the condition but not yet diagnosed—to estimate the corrected prevalence of OSA in 2023. This study used a 100% sample of Medicare fee-for-service (FFS) beneficiaries ≥65 years who were continuously enrolled between January 1, 2018, and December 31, 2023 (1-year baseline and 5 years of follow-up). OSA was defined as ≥1 inpatient claim or ≥2 outpatient claims with relevant diagnosis codes in any position (ICD-10: G47.30, G47.33, or G47.39). Using 2019 as the first follow-up year and assuming patients first diagnosed with OSA in 2020 or later also had the condition in 2019, we calculated the ratio of latent to diagnosed prevalence for 2019. This ratio was then applied to a separate cohort of beneficiaries continuously enrolled in 2023 to estimate the corrected prevalence of OSA for that year. Results The 5-year cohort included 14,939,076 beneficiaries, of whom 2,371,642 were identified as having OSA between 2019 and 2023, with approximately 49% initially diagnosed in 2019. Applying the ratio of latent to diagnosed prevalence to the 2023 cohort (N=22,121,159), the prevalence estimate of OSA increased from a diagnosed prevalence of 9.2% to a corrected prevalence of 18.9%. Conclusion By using a cohort of Medicare FFS beneficiaries and applying a mathematical approach to correct for underdiagnosis, the corrected prevalence of OSA in 2023 (18.9%) was estimated to be approximately 2.1-times higher than the diagnosed prevalence derived from cross-sectional claims data alone. This corrected epidemiologic estimate can help decision-makers better assess the budget impact of emerging therapeutics for OSA. Support (if any)

  PublisherOA PDFDOI

• HSD59 Disparities in Tardive Dyskinesia Diagnosis and Treatment Among the US Medicare Population

  Value in Health · 2025-07-01

  article
  PublisherDOI

Recent grants

• Antihypertensives and the Aging Brain

  NIH · $694k · 2019–2022

Frequent coauthors

• Shelly L. Gray

  Seattle University

  80 shared

• Joseph T. Hanlon

  University College Cork

  73 shared

• Douglas Barthold

  University of Washington

  63 shared

• Paul K. Crane

  University of Washington

  53 shared

• Jan Willem van Dalen

  Radboud University Medical Center

  46 shared

• Eric B. Larson

  Human Longevity (United States)

  45 shared

• Edo Richard

  Amsterdam University Medical Centers

  44 shared

• Willem A. van Gool

  University of Amsterdam

  40 shared

Education

• Other

  Butler University

• Ph.D., Clinical & Translational Science

  University of Pittsburgh School of Medicine

• M.S., Clinical Research

  University of Pittsburgh