# Therapeutic inertia

Therapeutic inertia (also known as clinical inertia) is a measurement of the resistance to therapeutic treatment for an existing medical condition. It is commonly measured as a percentage of the number of encounters in which a patient with a condition received new or increased therapeutic treatment out of the total number of visits to a health care professional by the patient. A high percentage indicates that the health care provider is slow to treat a medical condition. A low percentage indicates that a provider is extremely quick in prescribing new treatment at the onset of any medical condition.

## Calculation

There are two common methods used in calculating therapeutic inertia. For the following examples, consider that a patient has five visits with a health provider. In four of those visits, a condition is not controlled (such as high blood pressure or high cholesterol). In two of those visits, the provider made a change to the patient's treatment for the condition.

In Dr. Okonofua's original paper, this patient's therapeutic inertia is calculated as ${\displaystyle {\frac {h}{v}}-{\frac {c}{v}}}$ where h is the number of visits with an uncontrolled condition, c is the number of visits in which a change was made, and v is the total number of visits.[1] Therefore, the patient's therapeutic inertia is ${\displaystyle {\frac {4}{5}}-{\frac {2}{5}}=0.4=40\%}$.

An alternative, which avoids consideration of visits where the condition was already controlled and the provider should not be expected to make a treatment change, is ${\displaystyle 1-{\frac {c}{h}}}$. Using the above example, there are 2 changes and 4 visits with an uncontrolled condition. The therapeutic inertia is ${\displaystyle 1-{\frac {2}{4}}=0.5=50\%}$.

## Reception

Therapeutic inertia was devised as a metric for measuring treatment of hypertension. It has now become a standard metric for analysing treatment of many common comorbidities such as diabetes[2] and hyperlipidemia.[3] Both feedback reporting processes and intervention studies aimed at reducing therapeutic inertia have been shown to increase control of hypertension,[4] diabetes, and hyperlipidemia.

## References

1. ^ Eni C. Okonofua; Kit N. Simpson; Ammar Jesri; Shakaib U. Rehman; Valerie L. Durkalski; Brent M. Egan (January 23, 2006). "Therapeutic Inertia Is an Impediment to Achieving the Healthy People 2010 Blood Pressure Control Goals". Hypertension. 47 (2006, 47:345): 345–51. doi:10.1161/01.HYP.0000200702.76436.4b. PMID 16432045.
2. ^ Diabetes care: therapeutic inertia in doctors and patients
3. ^ Getting Patients to Their Lipid Targets: A Practical Approach to Implementing Therapeutic Lifestyle Changes
4. ^ Is blood pressure control to less than 140/less than 90 mmHg in 50% of all hypertensive patients as good as we can do in the USA: or is this as good as it gets?