Table 1.

Characteristics of the included studies

	*Hamilton et al, 2005¹³^–¹⁵*	Hippisley-Cox and Coupland, 2011¹⁶	Hippisley-Cox and Coupland, 2013¹⁷^,¹⁸ Tool for women/men	*Iyen-Omofoman et al, 2013¹²*	*Jones et al, 2007¹⁹*	*Jordan et al, 2013²⁰*
Outcome	Lung cancer risk within 2 years	Lung cancer risk within 2 years	Lung cancer risk within 2 years	Lung cancer risk within 4–12 months	Lung cancer risk within 3 years	Lung cancer risk within 0–1, 2–5, and 6–10 years
Cases	247	3785	2043^a/3351^a	12 074	301	239
Controls	1235	2 402 342	1 240 864^b/1 263 071^b	120 731	4511	17 451
Predictor variables examined	All symptoms, physical signs, and investigation results from the primary care records recorded in the 2 years prior to the cases’ lung cancer diagnosis. Entered into the analyses if they occurred in ≥2.5% of cases or controls	Haemoptysis, appetite loss, weight loss, cough, dyspnoea, tiredness, hoarseness, BMI, smoking status, chronic obstructive airways disease, Townsend deprivation score, family history of lung cancer, previous diagnosis of cancer apart from lung cancer, asthma, pneumonia, asbestos exposure, and anaemia	A large number of symptoms of any cancer and risk factors, including smoking, alcohol intake, age, BMI, haemoptysis, appetite loss, weight loss, cough, dyspnoea, tiredness, anaemia, abdominal pain, dysphagia, indigestion, neck lump, night sweats, venous thromboembolism, COPD^c	Age, sex, SES, smoking status, cough, haemoptysis, dyspnoea, chest/shoulder pain, weight loss, hoarseness, URTI, LRTI, non-specific chest infections, constipation, depressive disorders, COPD, outcome of blood tests, and number of GP consultations. All recorded 4–12 and 13–24 months before diagnosis	Age, sex, and haemoptysis	Age, sex, BMI, smoking status, drinking status, deprivation, and comorbidity, and musculoskeletal pain in the back, neck, shoulder, and hip
Predictor variables in final tool	Haemoptysis, cough, fatigue, dyspnoea, chest pain, weight loss and appetite loss, thrombocytosis, and abnormal spirometry	Haemoptysis, appetite loss, weight loss, cough, anaemia, BMI, smoking status, chronic, obstructive airways disease, Townsend deprivation score, and previous diagnosis of cancer apart from lung cancer (the latter was only included in the tool for females)	In both tools: haemoptysis, appetite loss, weight loss, cough, anaemia, dysphagia, indigestion, neck lump, venous thromboembolism, COPD, smoking status, Townsend deprivation score. In tool for males only: abdominal pain, night sweats	Age, sex, SES, smoking status, cough, weight loss, haemoptysis, chest/shoulder pain, dyspnoea, hoarseness, URTI, LRTI, non-specific chest infections, COPD, and number of GP consultations. Recorded 4–12 months before lung cancer diagnosis	Age, sex, and haemoptysis	Age, sex, BMI, smoking status, drinking status, deprivation, and comorbidity, and musculoskeletal pain in the back, neck, shoulder, and hip
Missing data handling	Unclear, but no imputation appears to have been performed	Multiple imputation to replace missing values for smoking status and BMI	Multiple imputation to replace missing values for smoking status, alcohol status, and BMI	No imputation has been performed. Low levels of missing data	No imputation appears to have been performed. All patients appear to be accounted for	Unclear, but no imputation appear to have been performed
Tool development	Multivariate analysis with univariate pruning. Used PPVs as the risk measure	Cox regression analysis with univariate pruning, age used as the underlying time variable	Multinomial logistic regression. Used RRs as the risk measure	Multivariate logistic regression with univariate pruning; used ORs as the risk measure	Calculation of PPVs for haemoptysis split by age group and sex	Cox proportional hazards regression analysis
Tool presentation	Tabular presentation of two tools (all patients, smokers) of the risks associated with single symptoms, repeat presentation of single symptoms, and symptom pairs. The PPVs ranged from 0.4% (cough, fatigue, both in all patients) to 17% (repeat presentation of haemoptysis in all patients)	Tabular presentation of two tools (males, females) with adjusted HRs for each predictor variable. The tools are also available on a website as a risk calculator	Tabular presentation of two tools (males, females) with adjusted RRs for each predictor variable. The tools are also available on a website as a risk calculator	As an equation with all the necessary β-coefficients for patients aged ≥40 years	Tabular format with the PPVs for haemoptysis split by age group and sex. These risk measures varied from 0.21% (in males aged <45 years) to 20.43% (in males aged ≥85 years)	Tabular format of adjusted HRs of musculoskeletal pain at the four locations. HRs were adjusted for age, sex, BMI, smoking status drinking status, deprivation, and comorbidity. Only back pain within the first year of follow up was associated with an increased risk of lung cancer (HR 1.67).
Tool availability	Fully available	Underlying computer code, or all the numbers underlying the tool do not appear to be readily available	Underlying computer code, or all the numbers underlying the tool do not appear to be readily available	Fully available, apart from the intercept	Fully available	HRs adjusted for other variables associated with risk of lung cancer, but their individual effects not reported
Validation	None	Internal	Internal	Internal	None	None
Impact study	Before-and-after study	No	No	No	No	No

BMI = body mass index. COPD = chronic obstructive pulmonary disease. HR = hazard ratio. LRTI = lower respiratory tract infection. OR = odds ratio. PPV = positive predictive value. RR = risk ratio. SES = socio-economic status. URTI = upper respiratory tract infection.
↵a Not reported separately for development and validation cohorts, so this is the total for both cohorts.
↵b Includes the number of cases (see ^a).
↵c Supplementary data available from the authors on request.