Diagnostic test guidelines based on high-quality evidence had greater rates of adherence: a meta-epidemiological study.

OBJECTIVES: To determine the association between the quality of guidelines for diagnostic tests (both the quality and reporting and the quality of the evidence underpinning recommendations) and nonadherence. STUDY DESIGN AND SETTING: We conducted a meta-epidemiological study. We previously published a systematic review that quantified the percentage of test use that was nonadherent with guidelines. For the present study, we assessed these guidelines using the Appraisal of Guidelines for Research & Evaluation (AGREE) II tool. We then assessed the quality of evidence underpinning recommendations within these guidelines using Grading of Recommendations Assessment, Development, and Evaluation (GRADE). Linear models were then constructed to determine the association between guideline nonadherence and (1) AGREE II score and (2) GRADE score. RESULTS: There was no significant association between AGREE II score and nonadherent testing (P = 0.09). There was a significant association between GRADE score and nonadherence: recommendations based on low-quality and very low-quality evidence had 38% (P < 0.01) and 24% (P = 0.02) more nonadherent testing, compared with recommendations based on high-quality evidence. CONCLUSION: Diagnostic test guideline recommendations based on high-quality evidence are adhered to more frequently.

Smoking cessation and survival in lung, upper aero-digestive tract and bladder cancer: cohort study.

BACKGROUND: The aim was to examine the association between smoking cessation and prognosis in smoking-related cancer as it is unclear that cessation reduces mortality. METHODS: In this retrospective cohort study from 1999 to 2013, we assessed the association between cessation during the first year after diagnosis and all-cause and cancer-specific mortality. RESULTS: Of 2882 lung, 757 upper aero-digestive tract (UAT) and 1733 bladder cancer patients 27%, 29% and 21% of lung, UAT and bladder cancer patients quit smoking. In lung cancer patients that quit, all-cause mortality was significantly lower (HR: 0.82 (0.74-0.92), while cancer-specific mortality (HR: 0.89 (0.76-1.04) and death due to index cancer (HR: 0.90 (0.77-1.05) were non-significantly lower. In UAT cancer, all-cause mortality (HR: 0.81 (0.58-1.14), cancer-specific mortality (HR: 0.84 (0.48-1.45), and death due to index cancer (HR: 0.75 (0.42-1.34) were non-significantly lower. There was no evidence of an association between quitting and mortality in bladder cancer. The HRs were 1.02 (0.81-1.30) for all-cause, 1.23 (0.81-1.86) for cancer specific, and 1.25 (0.71-2.20) for death due to index cancer. These showed a non-significantly lower risk in sensitivity analyses. CONCLUSIONS: People with lung and possibly UAT cancer who quit smoking have a lower risk of mortality than people who continue smoking.