How do we measure the adequacy of cancer pain management? Testing the performance of 4 commonly used measures and steps towards measurement refinement

Although pain is the most common and disabling cancer symptom requiring management, the best index of cancer pain management adequacy is unknown. While the Pain Management Index is most commonly used, other indices have included relief, satisfaction, and pain intensity. We evaluated their correlations and agreement, compared their biopsychosocial correlates, and investigated whether they represented a single construct reflecting the adequacy of cancer pain management in 269 people with advanced cancer and pain. Despite moderate-to-severe average pain in 52.8% of participants, 85.1% had PMI scores suggesting adequate analgesia, pain relief was moderate and satisfaction was high. Correlations and agreement were low-to-moderate, suggesting low construct validity. Although the correlates of pain management adequacy were multidimensional, including lower pain interference, neuropathic and nociceptive pain, and catastrophizing, shorter cancer duration, and greater physical symptoms, no single index captured this multidimensionality. Principal component analysis demonstrated a single underlying construct, thus we constructed the Adequacy of Cancer Pain Management from factor loadings. It had somewhat better agreement, however correlates were limited to pain interference and neuropathic pain. This study demonstrates the psychometric shortcomings of commonly used indices. We provide suggestions for future research to improve measurement, a critical step in optimizing cancer pain management. PerspectiveThe Pain Management Index and other commonly used indices of cancer pain management adequacy have poor construct validity. This study provides suggestions to improve the measurement of the adequacy of cancer pain management.