Case-patients were individually matched on surgery type, age and duration of surgical procedure in a ratio of one case-patient to two other members of the cohort.
As all matches were made from like-hospitals, all pairs were also matched on hospital type.
Of these, 231 pairs were also matched on diagnosis type (patients were matched by above criteria, but also had identical discharge diagnosis, e.g., Colles fracture, rib contusion); 45 pairs were matched on age, CTAS, and mode of arrival only; 25 pairs were matched on only age and CTAS; and 8 pairs were not CTAS matched, but differed by one.
Fourth, participants were not matched on trauma type or ethnicity.
Controls were matched on cancer type, gender, age in 10-year age groups, and calendar year of diagnosis in 5-year periods.
Case matched controls, matched on age, gender, type and number of chronic conditions selected from the McMaster Family Practice formed the control group.
Telephone surveys were conducted for 113 farms with a recent history of a bTB incident where their officially tuberculosis free status had been withdrawn (OTFW) (cases) and 224 controls with no history of a bTB incident, matched on location, production type and the rate of endemic bTB spread.
The primary match was with the age and gender, after which we matched on number and type of risk factors on a categorical basis.
A computer-generated scheme will randomize patients in a 1 1 ratio in blocks of assignments frequency matched on age and type of surgery (i.e., fusion or no fusion), resulting in 4 strata: (1) Age 21-59 and fusion; (2) Age 60-90 and fusion; (3) Age 21-59 ano no fusion; (4) Age 60-90 ano no fusion.
