Vascular Imaging in the Asymptomatic High-risk Cancer Population: A Role for Thrombosis Screening and Therapy Management

Positive predictive value and sensitivity of cancer-associated venous thromboembolism diagnoses in the Danish National Patient Register

INTRODUCTION

Hospital discharge diagnoses from administrative registries are frequently used in studies of cancer-associated venous thromboembolism, but the validity of International Classification of Diseases (ICD) codes for identifying such events is unknown.

MATERIALS AND METHODS

Using patient samples from the Danish National Patient Register, we calculated positive predictive values (PPV), i.e., the proportion of registered ICD codes, which could be confirmed after manual search of the electronic health record. Sensitivity was estimated in a sample of patients with imaging-verified venous thromboembolism but without prior knowledge about their ICD coding status. Sensitivity was calculated as the proportion of these patients, who were discharged with an ICD code for venous thromboembolism.

RESULTS

The overall PPV of an ICD-10 diagnosis of cancer-associated venous thromboembolism was 75.9 % (95 % confidence interval 71.3-80.0). In subgroups, the PPV was particularly low for recurrent venous thromboembolism (44.2 %), diagnoses in a secondary position (55.7 %), outpatient diagnoses (65.3 %), and diagnoses given at surgical (66.7 %), emergency wards (48.4 %), or via hospices/palliative teams (0 %). The overall sensitivity was 68 %, meaning 32 % of patients with cancer diagnosed in hospital with venous thromboembolism were discharged without any registered ICD code for venous thromboembolism.

CONCLUSIONS

The positive predictive value of an ICD diagnosis of cancer-associated venous thromboembolism in the Danish Patient Register was overall adequate for research purposes, but with notable variation across subgroups. Sensitivity was limited, as 1/3 of patients with venous thromboembolism were discharged without any relevant ICD code. Cautious interpretation of incidence of cancer-associated venous thromboembolism based on administrative register-based data is warranted.

Novel Insights in Venous Thromboembolism Risk Assessment Methods in Ambulatory Cancer Patients: From the Guidelines to Clinical Practice

Many cancer patients will experience venous thromboembolism (VTE) at some stage, with the highest rate in the initial period following diagnosis. Novel cancer therapies may further enhance the risk. VTE in a cancer setting is associated with poor prognostic, a decreased quality of life, and high healthcare costs. If thromboprophylaxis in hospitalized cancer patients and perioperative settings is widely accepted in clinical practice and supported by the guidelines, it is not the same situation in ambulatory cancer patient settings. The guidelines do not recommend primary thromboprophylaxis, except in high-risk cases. However, nowadays, risk stratification is still challenging, although many tools have been developed. The Khrorana score remains the most used method, but it has many limits. This narrative review aims to present the current relevant knowledge of VTE risk assessment in ambulatory cancer patients, starting from the guideline recommendations and continuing with the specific risk assessment methods and machine learning models approaches. Biomarkers, genetic, and clinical features were tested alone or in groups. Old and new models used in VTE risk assessment are exposed, underlining their clinical utility. Imaging and biomolecular approaches to VTE screening of outpatients with cancer are also presented, which could help clinical decisions.