Medical Necessity: Unexplained Clinical Variation in Care

I am a physician who writes and edits guidelines designed to assist in determining appropriate utilization of clinical resources. In a nutshell, the issue that pertains to today’s topic, medical necessity, is “unexplained clinical variation in care.”

What I mean by that is the fact that patients with similar clinical features and issues are treated very differently depending on variables unrelated to severity of illness, risk of deterioration, or clinical need.

What varies is the amount or intensity of care (testing, inpatient hospital care, procedures, etc.). This variation is called “unexplained,” as it persists even after taking into account items such as patient age, socioeconomic status, and illness details.

Importantly, a consistent finding is that this variation in the intensity of care is not associated with improved patient outcomes. That is, despite general belief to the contrary, more care is not necessarily better care.

This sort of variation has been identified across all manner of clinical entities, treatments, and variables. Care provided varies rather profoundly, for example, by geographic region in the U.S.. In general, more care, and a higher intensity of care, is rendered in the Northeast than in the West, for example.

Furthermore, this variation can be found within geographic regions, according to physician specialty and practice location, and variation exists even within individual groups of physicians. For example, unexplained variation exists between hospitals in the same or similar settings, and between individual clinicians within a single hospital or practice. This variation is not random, in that the same geographic areas, specialties, and individual doctors are found to provide more resource-intensive care than their counterparts.

What sort of variation do I mean, and how does this relate to medical necessity?

Important aspects of care to measure include those decisions and interventions that carry high cost and potential for risk of harm. An early measure was inpatient length of stay. A more recent measure has been the inpatient admission rate. For example, patients seen in the emergency department for the same reason and with similar clinical features are admitted to the hospital for inpatient care at rates that can vary significantly.

The cost ramifications of the admission decision are straightforward. Less appreciated is the consistent finding that being a patient in a hospital is quite risky, and therefore should only be considered when the benefit (that is to say, need) clearly outweighs the risk of harm. Study after study has found that somewhere in the neighborhood of 4 percent of hospitalized patients experience a preventable harm (for example wrong medication, wrong dose, hospital-acquired infection, etc.).

With this background, the importance of medical necessity becomes clear. Simply leaving it up to individual clinicians has resulted in the variation seen. At the same time, it is in no way a simple matter to standardize which patients need which type or amount of care.

For unexplained clinical variation, an implemented response is the expectation that clinical decisions and interventions (or at the least, payment for these interventions) be justifiable, that is, defendable according to some mutually accepted standard (in other words, documentation of medical necessity).

Various clinical tools, such as the MCG evidence-based guidelines, have been used by involved parties (for example, payors and auditors) to assist in the determination of when the clinical documentation supports a defined threshold of “medical necessity.”

It is crucial that whatever standards are applied, they be clinically “right,” that is, neither overly strict nor lenient, and seen as unbiased by all parties involved. An important means by which to achieve this standard and level of acceptance is to be strictly evidence-based. This entails the difficult process of searching for the best evidence, expertly interpreting the evidence, and incorporating new evidence when appropriate.

Correct usage of guidelines is likewise important. For example, the MCG guidelines are intended to supplement and support clinician-based decision-making, not replace it. They are designed to be used as guidance, not interpreted as inflexible rules. Our guidelines are very specific and detailed when the medical literature allows, and at the same time acknowledging of the “gray areas” of decision-making when the evidence is not as clear.

In either case, the guideline content is used to not only set a standard for how to determine severity of illness or need for a procedure, but also to provide a common set of key moving parts within any given clinical situation that should be documented and described.

It is through this consistent, appropriate use of evidence-based guidelines that the central, chronic issue of unexplained clinical variation can be recognized and addressed. Identification, determination, and documentation of medical necessity are the active ingredients in any attempt to reduce unexplained clinical variation in care.

Facebook
Twitter
LinkedIn

Bill Rifkin MD, FHM, FACP

Dr. Bill Rifkin is the associate vice president and managing editor of MCG Health. Dr. Rifkin oversees all research and content published by MCG Health that is focused on acute inpatient care. His expertise expands to hospital medicine and clinical care, where he has published multiple research documents.

Related Stories

Leave a Reply

Please log in to your account to comment on this article.

Featured Webcasts

AI, Audits, and the Future of the Revenue Cycle

Artificial intelligence is rapidly transforming healthcare revenue cycle operations, from coding and auditing to compliance and denials. Join industry leaders Pam Warren (MaineHealth) and Raemarie Jimenez (AAPC) for a live fireside chat exploring how AI is changing workflows, workforce roles, payer-provider dynamics, and compliance risk—and what organizations should be doing now to prepare.

June 17, 2026

Trending News

Featured Webcasts

CMS CRUSH: What You Need to Know About the Next Wave of Program Integrity and Payment Oversight

CMS CRUSH (Comprehensive Regulations to Uncover Suspicious Healthcare) signals a new era of data-driven program integrity oversight that extends far beyond coding and CDI. As federal scrutiny of claims, documentation, billing practices, provider enrollment, and payment accuracy intensifies, healthcare organizations must be prepared to identify and address vulnerabilities before they result in audits, denials, repayments, or enforcement actions. Join us for this timely webcast to learn what CMS CRUSH could mean for your organization and discover practical strategies to strengthen documentation, claims integrity, compliance readiness, and reimbursement defensibility.

July 14, 2026

Ask Dr. Hirsch: Clarifying Medicare’s Most Misunderstood Rules – Part 2

Medicare regulations are complex and even seasoned professionals struggle to apply them consistently. Due to overwhelming demand, Dr. Hirsch returns for Part 2 of Ask Dr. Hirsch: Clarifying Medicare’s Most Misunderstood Rules to answer even more of Medicare’s most misunderstood questions, covering inpatient status, observation, SNF access, Medicare Advantage denials, and more. Join Dr. Hirsch as he provides clear, referenced answers to real-world questions submitted by your peers, helping you navigate Medicare compliance with confidence and clarity.

June 18, 2026

Reengineering Utilization Management: Building an Adaptive Model for the New Payer Era

Traditional utilization management models can no longer keep pace with regulatory shifts, payer scrutiny, and operational pressures. In this webcast, Tiffany Ferguson, LMSW, CMAC, ACM, ACPA-C, introduces an Adaptive Model strategy that modernizes UM through role specialization, technology-driven workflows, and proactive, team-based processes. Attendees will learn how to restructure programs to improve efficiency, strengthen clinical collaboration, and enhance financial performance in a rapidly changing healthcare environment.

May 20, 2026

Compliance for the Inpatient Psychiatric Facility (IPF-PPS): Minimizing Federal Audit Findings by Strengthening Best Practices

Federal auditors are intensifying their focus on inpatient psychiatric facilities, using advanced data analytics to spotlight outliers and pursue high‑dollar repayments. In this high‑impact webcast, Michael Calahan, PA, MBA, Compliance Officer and V.P., Hospital & Physician Compliance, breaks down what regulators are really targeting in IPF-PPS admissions, documentation, treatment and discharge planning. Attendees will learn practical steps to tighten processes, avoid common audit triggers and protect reimbursement and reduce the risk of multimillion-dollar repayment demands.

April 9, 2026

Trending News

Prepare for the 2025 CMS IPPS Final Rule with ICD10monitor’s IPPSPalooza! Click HERE to learn more

Get 15% OFF on all educational webcasts at ICD10monitor with code JULYFOURTH24 until July 4, 2024—start learning today!

This Memorial Day, we honor those who gave all for our freedom. Take 20% off sitewide through May 29 with code MEMORIAL26 at checkout

CYBER WEEK IS HERE! Don’t miss your chance to get 20% off now until Dec. 1 with code CYBER25

CYBER WEEK IS HERE! Don’t miss your chance to get 20% off now until Dec. 2 with code CYBER24