The 25 Most Common Medical Diagnoses | Practice Fusion

If you were practicing medicine in October 2015, you undoubtedly remember the tremendous change associated with the transition from ICD-9 to ICD-10. All HIPAA-covered entities, including healthcare providers, healthcare clearing houses, electronic health record (EHR) vendors, and other business associates, were required to start using ICD-10 for medical billing and clinical documentation. ICD-10 is the tenth revision of the International Statistical Classification of Diseases and Related Health Problems (ICD) from the World Health Organization (WHO). Healthcare providers from all over the world were already using ICD-10 when those from the United States were required to do so.

In this article, we explore some of the history behind the switch from ICD-9 to ICD-10 and share the 25 most common medical diagnoses in 2021.

Why was the change from ICD-9 to ICD-10 necessary?

As you know, ICD is a diagnostic tool used for clinical, health management, and epidemiologic purposes, enabling analysis, assessment, and comparison of the incidence and prevalence of medical conditions, morbidity, and mortality data across the world. ICD-10 includes updated codes for signs and symptoms, diseases, procedures, abnormal findings, external causes of injury or disease, and social circumstances. Importantly, ICD-10 is much more than a simple updated version of ICD-9. Rather, it’s essentially a complete revamp and modernization of medical classifications, including nearly 70,000 new codes and more detailed 7-digit alphanumeric codes.^1,2,3

ICD-10 uses current medical terminology via an expanded coding format, enabling healthcare providers to capture greater detail within the code, providing much more specific information about the diagnosis. It is much more flexible than ICD-9, reflecting medical advances, new technologies, and diagnoses, while including more information about ambulatory and managed care as well as accidents and injuries. ICD-10 allows much greater specificity, including the ability to add laterality, combine diagnosis and symptom codes, and improve identification of conditions and disease processes to further promote research.^1,2,3

Further, this transition was required, by law, for covered entities—such as physicians, other healthcare providers, EHR vendors, and more–under the Health Insurance Portability and Accountability Act (HIPAA). It’s also mandatory for healthcare providers to bill using ICD-10 codes to receive payment for their services; otherwise, payment will be denied. Technically, the HIPAA ICD-10 code requirements apply solely to electronic transactions. Yet using ICD-10 for electronic submissions and ICD-9 for manual submissions would be extremely burdensome regarding time, duplicative efforts, error risk, resources, and other costs.^1,2,3

What are the major differences between ICD-10 and ICD-9?

Assessing your patient populations by ICD-10 for quality of care

To ensure optimal quality and managed care for your patients, it’s helpful to gain insight into trends in ambulatory care in the United States and in your area of the country. Identifying and tracking specific sets of patient populations is also key for fulfilling quality improvement measures as part of your practice’s Merit-based Incentive Payment Systems (MIPS) score.

Practice Fusion enables you to create custom reports of your practice’s patient populations based on using different combinations of clinical and demographic criteria along with the ability to save your customized reports for repeated generation. Practice Fusion’s Patient List Report provides several search parameters, including:

What are the top 25 ICD-10 codes in 2021?

It’s important to identify the kinds of conditions most encountered in ambulatory practices, particularly those specializing in primary care, enabling providers to determine the context for where they should focus disease interventions.

The most common ICD-10 diagnoses seen by U.S. primary care specialists include essential (primary) hypertension (I10); type II diabetes mellitus without complications (E11.9) and other specified diabetes mellitus without complications (E13.9); and hyperlipidemia, unspecified (E78.5).^4,5

It’s illustrative to compare the previous ICD-9 descriptions and codes against the new ICD-10 describers and codes or these frequent diagnoses regarding specificity and updated medical terminology:

The following chart shows 25 of the most common ICD-10 diagnoses as submitted by primary care specialists as well as the original ICD-9 codes.^4,5 Regarding numerical rank, these are not in any particular order, since different sources may list slightly different numerical rankings.

However, overall, the same diagnoses do tend to rise to the top. For example, some primary care practitioners may report more cases of essential hypertension than type II diabetes mellitus, whereas for others, the reverse may be true. Yet importantly, the following currently represents the most frequently reported ICD-10 codes and shows clear trends regarding primary cares’ patient populations and where disease interventions and proactive prevention methods should be focused.

ICD-9	ICD-9 Description	ICD-10	ICD-10 Description
401.9	unspecified essential hypertension	I10	essential (primary) hypertension
250.00	diabetes mellitus without mention of complications, type II or unspecified type, not stated as uncontrolled	E11.9 E13.9	type II diabetes mellitus without complications other specified diabetes mellitus without complications
272.4	other and unspecified hyperlipidemia	E78.5	hyperlipidemia, unspecified (*There are more specific ICD-10 codes available, if applicable, e.g., pure hypercholesterolemia [E78.0].)
724.5	Lumbago	M54.5	low back pain
V70.0	routine general medical examination at a healthcare facility	Z00.00	encounter for general adult medical examination without abnormal findings
496	chronic airway obstruction, not elsewhere classified	J44.9	chronic obstructive pulmonary disease (COPD), unspecified (*There are more specific ICD-10 codes, if applicable, e.g., chronic obstructive pulmonary disease with acute lower respiratory infection [J44.0]; an additional code is required to identify infection type.)
427.31	atrial fibrillation	I48.0 I48.1 I48.2 I48.91	Paroxysmal atrial fibrillation Persistent atrial fibrillation Chronic atrial fibrillation Unspecified atrial fibrillation
789.00	abdominal pain, unspecified site	R10.9	abdominal pain, unspecified (*There are more specific ICD-10 codes, if applicable, e.g., acute abdominal pain [R10.0)], upper abdominal pain, unspecified [R10.10], right upper quadrant pain [R10.11], left upper quadrant pain [R10.12])
414.00	coronary artery atherosclerosis of unspecified type of vessel, native, or graft	n/a*	*no equivalent in ICD-10; more clinical specifics are required to determine proper ICD-10 code. (However, one of the most frequent ICD-10 codes used by primary care specialists is “atherosclerotic heart disease of native coronary artery without angina pectoris” [I25.10].)
338.4	need for prophylactic vaccination and inoculation against unspecified single disease	Z23	encounter for immunization (ICD-10 code required first for any routine childhood examination.)
599.0	urinary tract infection, site not specified	N39.0	urinary tract infection, site not specified (*Required to use an additional ICD-10 code to specify cause of infection [B95-97].) (*There are also more specific ICD-10 codes available, if applicable, e.g., acute cystitis without hematuria [N30.00], acute cystitis with hematuria [N30.01], interstitial cystitis chronic without hematuria [N30.10].)
300.00	anxiety state, unspecified	F41.9	anxiety disorder, unspecified (*There are more specific ICD-10 codes, if applicable, e.g., generalized anxiety disorder [F41.1].)
311	depressive disorder, not elsewhere classified	F32.9	major depressive disorder, single episode, unspecified (*There are more specific ICD-10 codes, if applicable, e.g., major depressive disorder, single episode, mild [F32.0], major depressive disorder, single episode, moderate [F32.1], etc.)
530.81	esophageal reflux	K21.9 K21.0	gastroesophageal reflux disease without esophagitis gastroesophageal reflux with esophagitis
729.5	pain in limb	M79.609	pain in unspecified limb (*There are more specific ICD-10 codes, if applicable, e.g., pain in right arm [M79.601], pain in left arm [M79.602], pain in arm, unspecified [M79.603], pain in right leg [M79.604], pain in left leg [M79.605], pain in leg, unspecified [M79.606], etc.
786.50	chest pain, unspecified	R07.9	chest pain, unspecified (*There are more specific ICD-10 codes available, if applicable, e.g., chest pain on breathing [R07.1] or pleurodynia [R07.81].)
780.79	other malaise and fatigue	R53.0 R53.1 R53.81 R53.83 G93.3	neoplasm (malignant) related fatigue (*Required to first code the associated neoplasm.) weakness other malaise other fatigue postviral fatigue syndrome
465.9	acute upper respiratory infections of unknown site	J06.9 J39.8	acute upper respiratory infection, unspecified other specified diseases of the upper respiratory tract
486	pneumonia, organism unspecified	J18.9	pneumonia, unspecified organism (*Required to code associated influenza first, if applicable [J09.X1, J10.0-, J11.0-].)
466.0	acute bronchitis	J20.9	acute bronchitis, unspecified (There are also more specific ICD-10 codes, if applicable, e.g., acute bronchitis due to parainfluenza virus [J20.4], acute bronchitis due to respiratory syncytial virus [J20.5], acute bronchitis due to rhinovirus [J20.6], etc.)
719.46	pain in joint, lower leg	M25.561	pain in right knee pain in left knee pain in unspecified knee
428.0	congestive heart failure, unspecified	I50.9	heart failure, unspecified (*There are also more specific ICD-10 codes, if applicable, e.g., left ventricular failure [I50.1], acute systolic (congestive) heart failure [I50.21], chronic systolic (congestive) heart failure [I50.22], etc.)
244.9	unspecified hypothyroidism	E03.9	hypothyroidism, unspecified (*There are more specific ICD-10 codes, if applicable, e.g., congenital hypothyroidism with diffuse goiter [E03.0] or congenital hypothyroidism without goiter [03.1].)

Reviewing such data can be critical in collaborative decision-making with patients at the center of and as part of the discussion. This small example shows the value of taking advantage of ICD-10’s specificity when diagnosing patients and billing visit encounters via Practice Fusion enabling you to generate and evaluate such data to learn more about your patients’ needs, to ensure optimal quality of care, and to fulfill quality improvement measures critical to your patients.

References

1. Kurusz S, Rubin C, Morisy LR. Bulletin of the American College of Surgeons. The transition to ICD-10 before October 1 compliance deadline. June 1, 2015. Accessed September 3, 2021.
   
2. Blue Cross Blue Shield of Michigan. Primary Care ICD-10-CM Coding Tip Sheet: Overview of key chapter updates for primary care (primary care here includes internal medicine, family practice, and general practice). Accessed September 3, 2021. [https://www.bcbsm.com/content/dam/public/Providers/Documents/help/faqs/icd10-tipsheet-primarycare.pdf]
   
3. American Medical Association. Fact Sheet: Preparing for the ICD-10 code set October 1, 2015 compliance date. The differences between ICD-9 and ICD-10. Last updated October 2, 2014. Accessed September 3, 2021. https://www.ama-assn.org/sites/ama-assn.org/files/corp/media-browser/premium/washington/icd10-icd9-differences-fact-sheet_0.pdf
   
4. Definitive Healthcare, LLC. 10 most common diagnoses and procedures in primary care. Last accessed on September 3, 2021. https://www.definitivehc.com/blog/10-most-common-diagnoses-in-primary-care
   
5. American Academy of Professional Coders (AAPC). Fast forward: ICD:10 top 50 codes, family practice. Last accessed on September 3, 2021. https://www.aapc.com/icd-10/documents/2015_fastforward_familypractice_press.pdf