Tackling therapeutic inertia: role of treatment data in quality indicators

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Abstract
Evidence from observational studiesPoor control of hypertension is defined as a failure to meet recommended blood pressure goals. Barriers to controlling hypertension include patient factors, such as non-adherence to lifestyle advice or drug treatment,4 and healthcare provider factors, including the organisation or environment where care is delivered.1 5 6 As measurement of quality of risk factor management has become routine, more attention has been paid to provider factors generally, and particularly therapeutic inertia—the failure to start new drugs or increase the dose in patients with an abnormal clinical measurement.7Observational studies in the United States have found that therapeutic inertia is common in hypertension,1w1 w2 diabetes,w3 w4 and hypercholesterolaemia,w5 and is associated with poor control of risk factors known to be linked to longer term health problems.w5 w6 In our 2002 observational study of 560 hypertensive patients from eight general practices in Tayside, Scotland, adherence to blood pressure lowering treatment was high (mean 91%).8 However, in terms of the British Hypertension Society guidelines at the time,9 360/498 (72%) had suboptimal blood pressure at their last recorded measurement (≥140/85 mm Hg without diabetes, ≥140/80 mm Hg with diabetes) and 299/492 (61%) had suboptimal blood pressure recorded in two successive consultations, 211 (70%) of whom were taking fewer than three antihypertensive drugs.10Table 1⇓ shows the proportion of consultations in which patients with inadequate control did not have their treatment intensified. Treatment was not intensified in nearly half (45%) of consultations in which the patients had a single suboptimal blood pressure reading (box). Similarly, no intensification occurred in 36% of consultations after two successive suboptimal blood pressure readings, and 27% of those taking fewer than three drugs. View this table: In this window In a new window Table 1 Numbers (percentages) of final consultations in 2002 in which treatment was not intensified among patients with poor control of blood pressureTreatment intensification: definition and predictorsTreatment intensification was defined as either the prescription of a new class of antihypertensive drug or an increase in dose of an already prescribed drug. Intensification was considered to have happened if treatment was changed within six weeks of the consultation, providing that blood pressure was measured again in that period. This was to allow for delay in changing treatment when blood pressure was measured in secondary care or by primary care nurses, with subsequent prescription by general practitioners.We examined predictors of treatment intensification using a random effects logistic regression model to account for repeated consultations by patients over time, and crude and adjusted odds ratios were calculated. To adjust for changes of treatment that were not an intensification in response to a suboptimal blood pressure, we chose reference categories for blood pressure variables (systolic <140 mm Hg, diastolic <80 mm Hg) below which treatment changes can be assumed to be solely due to other factors (management of coexisting conditions or drug side effects). Odds ratios therefore reflect treatment intensification above this baseline rate of treatment change.Therapeutic inertia persisted in a substantial proportion (16-30%) of consultations when blood pressure control was defined in terms of the less stringent audit criteria. Multivariable analysis showed a strong, graded relation between treatment intensification and increasing systolic or diastolic blood pressure (table 2⇓). However, doctors were more likely to intensify therapy when blood pressure exceeded 150/85 mm Hg for the current consultation or 150/90 mm Hg for the previous consultation. Intensification was progressively less likely as the number of antihypertensive drugs being taken increased. Our findings are consistent with data from a recent large US study, in which a third of patients with persistent blood pressure ≥160/100 mm Hg had no change in treatment or spontaneous return to lower blood pressure over six months (although the study did not examine if this reflected prescribing decisions or patient adherence).11View this table: In this window In a new window Table 2 Association of patient and consultation variables with intensification of treatment