Descriptive Evaluation in Outpatient Follow-Up of Direct LDL-C in Patients with Elevated Triglycerides and Diabetes.

Introduction: An annual fasting lipid panel (FLP) is recommended for patients with diabetes, with more frequent testing advised during the escalation of cholesterol-lowering therapy. However, the calculated low-density lipoprotein cholesterol (LDL-C) using the Friedewald equation becomes unreliable when triglycerides are ≥400 mg/dL. In such cases, providers must order a separate direct LDL-C assay to obtain accurate results. Failing to do so may lead to missed opportunities for therapy intensification. This study examined an institution's current practices for following up on invalid LDL-C results, especially considering the stringent LDL-C targets outlined in recent guidelines and consensus statements.

Methods: The authors conducted a retrospective chart review across 13 outpatient clinics within a single health system over five years. The study included patients aged 40-75 with diabetes who had at least one invalid LDL-C result. They assessed the frequency of ordering a direct LDL-C assay within seven days of an invalid LDL-C result.

Results: Out of 1,364 unique invalid FLPs, 97 (7.1%) met the criteria for the primary outcome. The rate of therapy escalation was not numerically affected by whether a direct LDL-C was ordered or the provider type. However, patients without a direct LDL-C ordered within seven days showed a trend towards more frequent therapy escalation (16.2%, n = 25/154) compared to those with a direct LDL-C (14.9%, n = 23/154).

Conclusions: The current practice at this institution of manually ordering a direct LDL-C assay to verify invalid LDL-C results poses a risk of missing necessary guideline-directed therapeutic intensification. This process may be improved by implementing a reflex direct LDL-C assay.