Low-density lipoprotein-cholesterol (LDL-C) greater than 100 mg/dL as a quality indicator: locating risk in person, place and time.

Rationale, Aims And Objectives: Achieving control over elevated lipid parameters, particularly low-density lipoprotein (LDL)-cholesterol, is an acknowledged quality indicator in primary care. The Centers for Disease Control and Prevention (CDC)'s model for investigation of outbreaks (person-place-time) can be applied to the analysis of quality indicators.

Methods: A sample of 322 family medicine patients for whom lipid levels were ordered was extracted. LDL > 100 mg/dL was cross-tabulated by personal characteristics [age group, gender, body mass index (BMI), diagnoses], month (time) and ordering department (place).

Results: Age (except one age category), gender, time and location were not related to LDL > 100 mg/dL after adjustment for covariates. All levels of BMI above normal elevated the risk of LDL > 100 mg/dL [BMI 25-29.9: odds ratio (OR) = 3.41, confidence interval (CI) = 1.61-7.23, P = 0.0014; BMI 30-34.9: OR = 2.93, CI = 1.28-6.70, P = 0.0109; BMI ≥ 35: OR = 2.75, CI = 1.19-6.37, P = 0.0181]. Patients with coronary artery disease (CAD) and diabetes mellitus (DM) were at reduced risk for LDL > 100 mg/dL (CAD: OR = 0.47, CI = 0.24-0.91, P = 0.0254; DM: OR = 0.28, CI = 0.14-0.55, P = 0.0002).

Conclusion: An outbreak investigation model is useful for analysing variations in this quality indicator. Patients with higher BMI and those not diagnosed with CAD or DM type I/II may be considered for intensified lipid lowering using quality improvement efforts. These might include counselling for lifestyle changes or medication therapy depending upon their calculated cardiac risk.