ArticleMedical care2012
Estimating proximity to care: are straight line and zipcode centroid distances acceptable proxy measures?
Article in Medical care, 2012. The graph could read no effect estimate from its abstract, so it casts no vote on the map. Cited by 38 papers, 1 of them a synthesis that pooled it.
What it found
Each row is one number read from the abstract, on the scale the paper reported it, with its interval. Left of the dashed line favours the treatment, right favours the comparator. Under each row is the sentence it came from. New to these charts? A ten-minute tutorial.
The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
Trials whose registry record cites this paper, or whose number appears in the abstract. A trial that started after this paper was published is citing it as background, not reporting it.
Neither the registry nor the abstract names a trial number. If this is a trial report, that itself is worth knowing.
Who cites it
38 citing papers in PubMed, 1 synthesis or guideline pooled it.
- Pooled it
- Disparities in genetic services utilization in a random sample of young breast cancer survivors.Genetics in medicine : official journal of the American College of Medical Genetics · 2019Trial
- Distance to Care, Regional Context, and Survival in Early-Onset Colorectal Cancer.Journal of surgical oncology · 2026Article
- Racial and ethnic differences in presentation and postoperative recovery after transsphenoidal surgery for cushing disease.Journal of neuro-oncology · 2026Article
- Travel Distance, Urbanicity, and Cardiac Rehabilitation Participation in Medicare Beneficiaries.JACC. Advances · 2026Article
- The Road to Cancer Care: Understanding How Far Owners Travel for Their Pets' Oncology Treatment.Veterinary sciences · 2025Article
- Assessing Healthcare Equity in Orthopaedic Surgery: An Analysis of Over 24,000 Surgical Cases.Journal of the American Academy of Orthopaedic Surgeons. Global research & reviews · 2024Article
- Influence of Demographic and Socioeconomic Factors on Hospital Distance for Total Knee Arthroplasty.Arthroplasty today · 2023Article
- Ambulance use and subsequent fragmented hospital readmission among older adults.Journal of the American Geriatrics Society · 2023Article
- Decarbonization, population disruption and resource inventories in the global energy transition.Nature communications · 2022Article
- Demographics of Patients Traveling Notable Distances to Receive Total Knee Arthroplasty.Journal of the American Academy of Orthopaedic Surgeons. Global research & reviews · 2022Article
- Evaluating a Tobacco Treatment Program's Transition to Telehealth Using a Social Determinants of Health Lens.Nicotine & tobacco research : official journal of the Society for Research on Nicotine and Tobacco · 2022Article
- Racial and Socioeconomic Differences in Distance Traveled for Elective Hip Arthroplasty.Journal of the American Academy of Orthopaedic Surgeons. Global research & reviews · 2022Article
- Distance as explanatory factor for sexual health centre utilization: an urban population-based study in the Netherlands.European journal of public health · 2021Article
- Influence of Geographic Access on Surgical Center Readmissions After Index Congenital Heart Surgery.The Journal of pediatrics · 2021Article
- Observational
- The Relationship of Travel Distance to Postoperative Follow-up Care on Glaucoma Surgery Outcomes.Journal of glaucoma · 2020Article
- Racial/Ethnic and Insurance Status Disparities in Distance Traveled to Access Children's Hospital Care for Severe Illness: the Case of Children with Leukodystrophies.Journal of racial and ethnic health disparities · 2020Article
- Genetic Testing and Surveillance of Young Breast Cancer Survivors and Blood Relatives: A Cluster Randomized Trial.Cancers · 2020Article
- Comparison of Number and Geographic Distribution of Pediatric Subspecialists and Patient Proximity to Specialized Care in the US Between 2003 and 2019.JAMA pediatrics · 2020Article
Corrections and comments
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Authors and funding
4 authors.
Funding
Abstract
backgroundSpatial accessibility of healthcare may be measured by proximity of patient residence to health services, typically in driving distance or driving time. Precise driving distances and times are rarely available. Although straight line distances between zipcode centroids and between precise address locations are used as proxy measures for distance to care, the accuracy of these measures has received little study.
methodsAmong a cohort of Medicare beneficiaries, actual driving distances and times between patient residence and clinic were obtained from commercial software (MapQuest). We used a split-sample design to build and validate linear regression models that predict actual driving distances and times from estimated distances between zipcode centroids and between precise residential and hospital locations, adjusting for urban/suburban/rural residential status.
resultsOn average, predicted driving distances and times were larger than actual values. Zipcode centroid distances alone predicted longer driving distances than observed values: rural +19% (3.2 miles), suburban +23% (3.7 miles), and urban +27% (2.0 miles). Predicted time was 36% (9.4 min) longer in rural, 32% (6.8 min) longer in suburban, and 38% (4.7 min) longer in urban areas than observed values. Including urban/suburban/rural categorization of residence improved the accuracy of predicted driving distance and time for suburban and urban areas but diminished accuracy for rural areas. Similar trends were observed for distance estimates from precise locations.
conclusionsDistances between zipcode centroids and precise residential/hospital locations provide reasonable estimates of driving distance and time for epidemiologic research. Estimates are improved for suburban and urban residences when data are augmented by urban categorization.
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Registered trials
Read under generation 80e0d062 · epoch 390. Bibliography from PubMed, PubMed Central and OpenAlex; grants from NIH RePORTER; trial links from ClinicalTrials.gov; estimates, votes and beliefs from the OpenQuestion graph.