Can a urine dipstick test be used to assess smoking status in patients undergoing planned orthopaedic surgery? a prospective cohort study.
OBJECTIVE
Smoking is associated with post-operative complications but smokers often under-report the amount they smoke. Our objective was to determine whether a urine dipstick test could be used as a substitute for quantitative cotinine assays to determine smoking status in patients.


METHODS
Between September 2013 and July 2014 we conducted a prospective cohort study in which 127 consecutive patients undergoing a planned foot and ankle arthrodesis or osteotomy were included. Patients self-reported their smoking status and were classified as: 'never smoked' (61 patients), 'ex-smoker' (46 patients), or 'current smoker' (20 patients). Urine samples were analysed with cotinine assays and cotinine dipstick tests.


RESULTS
There was a high degree of concordance between dipstick and assay results (Kappa coefficient = 0.842, p < 0.001). Compared with the quantitative assay, the dipstick had a sensitivity of 88.9% and a specificity of 97.3%. Patients claiming to have stopped smoking just before surgery had the highest rate of disagreement between reported smoking status and urine testing.


CONCLUSIONS
Urine cotinine dipstick testing is cheap, fast, reliable, and easy to use. It may be used in place of a quantitative assay as a screening tool for detecting patients who may be smoking. A positive test may be used as a trigger for further assessment and counselling. Cite this article: Bone Joint J 2016;98-B:1418-24.
Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, HA7 4LP, UK.
A
A
Salandy
Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, HA7 4LP, UK.
K
K
Malhotra
Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, HA7 4LP, UK.
A J
AJ
Goldberg
Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, HA7 4LP, UK.
N
N
Cullen
Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, HA7 4LP, UK.
D
D
Singh
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003367:Cotinine / Q000652:urine*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D007592:Joint Diseases / Q000601:surgery*; D008297:Male; D008875:Middle Aged; D019637:Orthopedic Procedures; D057234:Preoperative Period; D011446:Prospective Studies; D012307:Risk Factors; D057566:Self Report; D012907:Smoking / Q000453:epidemiology / Q000652:urine*; D013997:Time Factors; D006113:United Kingdom / Q000453:epidemiology; D016482:Urinalysis; D055815:Young Adult
D003367:Cotinine
Cotinine; Orthopaedic surgery; Smoking; Urine dipstick