Health and Medical News and Resources

General interest items edited by Janice Flahiff

Diagnostic Codes & Misleading Clinical Assumptions (Explains Why Pneumonia Cases Were Underreported Nationwide)

Bottom line…an author had used codes which underreported pneumonia cases by not taking into account diagnoses where pneumonia was a secondary diagnosis


From NLM Director’s Comments Transcript
Diagnostic Codes & Misleading Clinical Assumptions: 05/29/2012

Purported declines in pneumonia hospitalization and mortality rates were misleading because a standardized clinical diagnostic coding system was interpreted one-dimensionally, find an illuminatingstudy and an accompanying editorial recently published in the Journal of the American Medical Association.

Both the study and the editorial suggest subtle revisions in the use of diagnostic codes and related reimbursement procedures can impact hospital data and alter inferences about patient results as well as the quality of health care provided by U.S. hospitals, clinics, and health care providers….

n the study, five authors initially found a 27 percent decline in hospitalization and a 28 percent decline in mortality rates from pneumonia during 2003-2009 by using a patient results database that is undergirded by a nationally used diagnostic code system. The coding system is called the International Classification of Diseases, Ninth Revision, Clinical Modification, which is often referred to as ICD-9-CM. ICD-9-CM is used by hospitals, clinics, and health care providers nationwide to code patient diagnoses and is a foundation for administrative and patient records as well as insurance billing.

The study’s authors explain the Nationwide Input Sample (grounded in ICD-9-CM diagnostic codes) suggested there were significant improvements in hospitals and clinics across the U.S. in the treatment of pneumonia, which also were reported in other, smaller studies.

However, the study’s authors checked the identical dataset for hospitalization rates by using a more multidimensional definition of pneumonia within ICD-9-CM codes. The authors asked how many patients were diagnosed with sepsis and respiratory failure with a secondary diagnosis of pneumonia during the same time period? The authors found the hospitalization and respiratory rates increased by 178 percent and nine percent respectively for patients diagnosed with sepsis and respiratory failure with a secondary diagnosis of pneumonia.

When the study’s authors then combined a primary and secondary pneumonia diagnoses from the same dataset, they found an overall 12 percent decline in pneumonia-related admissions and a six percent increase in mortality occurred from 2003-2009. In other words, the addition of two other codes for pneumonia diagnoses partially refuted the initial reports of highly reduced hospitalization and mortality from pneumonia.

The study’s authors write (and we quote) ‘the results suggest that secular trends in documentation and coding, rather than improvements in actual outcomes, may explain much of the observed change in this and other studies’ (end of quote).

The study’s authors explain the current research is the first to assess hospitalization and mortality rates using a multidimensional diagnostic definition of pneumonia.

Similarly, the editorial’s authors write and we quote): ‘nuances in the assignment of principal and secondary diagnoses (in ICD-9-CM codes) can also affect assessment of hospital performance’ (end of quote).

Among other examples, the editorial’s authors add the use of sepsis as a diagnosis among patients with pneumonia may have increased significantly from 2003-2009 because the reimbursement potential for sepsis (based on diagnosis related groups) was higher than pneumonia during this period. The editorial’s authors write (and we quote): ‘Under prospective payment, there is a wide variation in reimbursement for different diagnosis related groups (DRGs), creating incentives to identify principal diagnoses associated with higher reimbursing DRGs’ (end of quote).

While the editorial’s authors acknowledge ICD-9-CM codes and DRGs (as well as other, related information) make it easier to use administrative data to assess health care delivery and quality of care, they underscore it is important to judiciously interpret the methods and findings. The editorial’s authors conclude (and we quote): ‘the potential for misleading interpretation of findings based on naïve analysis of administrative data and a lack of appreciation of the nuances in diagnostic coding will continue to be a problem’ (end of quote).

Meanwhile,’s health insurance health topic page provides insights into the bottom line byproduct of diagnostic codes that impactpatients and health consumers — how to pay for a provider’s or health organization’s charges.’s health insurance health topic page provides two overviews of health insurance from the American Academy of Family Physicians in the ‘start here’ section. A helpful guide to 10 ways to make health benefits work for you (from the U.S. Department of Labor) also is available in the ‘start here’ section.

A website from the American College of Physicians and the American Association of Retired Persons (available in the ‘related issues’ section) helps you understand some of the pending changes in health insurance associated with the comprehensive health care law the U.S. Congress passed in 2010.’s health insurance health topic page additionally contains updated research summaries, which are available within the ‘research’ section. Links to the latest pertinent journal research articles are available in the ‘journal articles’ section. From the health insurance health topic page, you can sign up to receive email updates with links to new information as it becomes available on MedlinePlus.

To find’s health insurance health topic page, type ‘health insurance’ in the search box on’s home page, then, click on ‘health insurance (National Library of Medicine).’ also contains related health topic pages on: Financial Assistance, Managed Care, Medicaid, Medicare, and Medicare Prescription Drug Coverage.

Before I go, this reminder……. is authoritative. It’s free. We do not accept advertising …and is written to help you.



June 4, 2012 Posted by | Health Statistics | , , | Leave a comment


%d bloggers like this: