Agreement among measures examining low-value imaging for low back pain.

OBJECTIVES

To quantify the extent of patient-level agreement among 3 published measures of low-value imaging for acute low back pain (LBP).

STUDY

DESIGN

In this retrospective cohort study using commercial insurance claims from MarketScan, we assessed 3 published measures of low-value imaging for agreement in identifying LBP diagnoses (denominator), red-flag diagnoses (denominator exclusions), and imaging procedures (numerator).

METHODS

Using a cohort of patients, aged 18 to 64 years, with a diagnosis of LBP in 2014, we assessed agreement surrounding both the overuse event (imaging procedures) and inclusion in the reference population (LBP definition and exclusion diagnoses) using percent agreement and Fleiss κ among 3 overuse measures.

RESULTS

In our cohort of 1,835,620 patients with acute LBP, the 3 measures agreed 100% on the presence of acute LBP and also had excellent agreement (99%; κ = 0.98) in identifying imaging for LBP. However, there was substantial disagreement on whom to exclude for red-flag diagnoses, leading to lower agreement (75%; κ = 0.61) on whom to include in the reference population of acute LBP without red flags, among whom imaging for LBP is considered of low value.

CONCLUSIONS

Our findings demonstrate the need for further consensus surrounding how to translate guideline recommendations to administrative measures that assess overuse of imaging for acute LBP, particularly with respect to defining which patients should be excluded from the measures. This finding is also important for other overuse measures that rely on exclusions.