Measuring the frequency and variation of unnecessary care across Canada

Table 2 Patient- and provider-level characteristics and rates of preoperative cardiac testing within 60 days prior of a low-risk surgical procedure in Alberta (N = 88,131 procedures) and Saskatchewan (N = 35,072 procedures) between June 2012 and March 2013

			Preoperative cardiac testing
Characteristic	Province^a	No. procedures	Rate per 100^b	Odds Ratio (95% CI)^c
Patient-level**
Age
18–44 [ref]	Saskatchewan	5476	15.6	1.00
18–44 [ref]	Alberta	16,736	19.0	1.00
45–64	Saskatchewan	13,186	37.6	2.92 (2.63–3.23)*
45–64	Alberta	33,759	38.3	3.40 (3.18–3.62)*
65+	Saskatchewan	16,410	46.8	4.56 (4.11–5.06)*
65+	Alberta	37,636	42.7	4.89 (4.56–5.24)*
Sex
Male [ref]	Saskatchewan	16,134	46.0	1.00
Male [ref]	Alberta	40,945	46.5	1.00
Female	Saskatchewan	18,938	54.0	0.95 (0.90–1.00)
Female	Alberta	47,186	53.5	0.96 (0.93–1.00)
Comorbidity^d
No comorbidity [ref]	Saskatchewan	28,640	81.7	1.00
No comorbidity [ref]	Alberta	63,526	72.1	1.00
Comorbidity	Saskatchewan	6432	18.3	1.84 (1.73–1.96)*
Comorbidity	Alberta	24,605	27.9	1.90 (1.82–1.97)*
Provider-level***
Anesthesiology consult
No [ref]	Saskatchewan	34,077	97.2	1.00
No [ref]	Alberta	85,055	96.5	1.00
Yes	Saskatchewan	995	2.8	6.16 (5.34–7.11)*
Yes	Alberta	3076	3.5	10.9 (9.99–11.9)*
Medical consult
No [ref]	Saskatchewan	32,432	92.5	1.00
No [ref]	Alberta	82,150	93.2	1.00
Yes	Saskatchewan	2640	7.5	6.30 (5.78–6.76)*
Yes	Alberta	5981	6.8	9.93 (9.36–10.5)*

Notes: * P ≤ .05; **patient characteristics are adjusted for each other and procedure type; *** provider characteristics are adjusted for each other and procedure type; CI = confidence interval; [ref] = reference category
^a separate models were created for each province versus including province as a dichotomous variable
^b rate is the observed rate (# tests/n) at index procedure – (1 to 60 d) for each patient in denominator
^c odds ratio and 95% CI estimates based on multiple binary logistic regression models and adjusted for procedure type (endoscopic, ophthalmologic, or other)
^d indicator variable representing whether patient had history of any of the following comorbidities: coronary artery disease, congestive heart failure, atrial fibrillation, other cardiac arrhythmia, cardiac valvular disease, renal disease, previous cardiovascular disease, peripheral vascular disease, venous thromboembolism, COPD, diabetes, hypertension and/or asthma

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