Validity of urges to smoke measures in predicting smoking relapse during treatment in primary care

In the context of smoking cessation treatment in primary care, identifying patients at the highest risk of relapse is relevant. We explored data from a primary care trial to assess the validity of two simple urges to smoke questions in predicting long-term relapse and their diagnostic value. Of 295 patients who received behavioural support and varenicline, 180 were abstinent at week 9. In this subgroup, we measured time spent with urges to smoke (TSU) and strength of urges to smoke (SUT; both scales 1 to 6 = highest). We used separate regression models with TSU or SUT as predictor and relapse from week 9-26 or week 9-52 as an outcome. We also calculated the sensitivity (SP), specificity and positive predictive values (PPV) of TSU and SUT in correctly identifying patients who relapsed at follow-up. The adjusted odds ratios (aOR) for predicting relapse from week 9-26 were 1.74 per point increase (95% CI = 1.05-2.89) for TSU and 1.59 (95% CI = 1.11-2.28) for SUT. The aORs for predicting relapse from week 9-52 were 2.41 (95% CI = 1.33-4.37) and 1.71 (95% CI = 1.14-2.56), respectively. Applying a cut-point of ≥3 on TSU resulted in SP = 97.1 and PPV = 70.0 in week 9-26, and SP = 98.8 and PPV = 90.0 in week 9-52. Applying a cut-point of ≥4 on SUT resulted in SP = 99.0 and PPV = 85.7 in week 9-26, and SP = 98.8 and PPV = 85.7 in week 9-52. Both TSU and SUT were valid predictors of long-term relapse in patients under smoking cessation treatment in primary care. These simple questions may be useful to implement in primary care.Trial registration: Dutch Trial Register (NTR3067).