Predictive Factors for not Undergoing RNA Testing in Patients Found to Have Hepatitis C Serology and Impact of an Automatic Alert

Dalia Morales-Arraez; Ana Alonso-Larruga; Felicitas Diaz-Flores; Jose A. García Dopico; Antonia de Vera; Enrique Quintero; Manuel Hernández-Guerra


J Viral Hepat. 2019;26(9):1117-1123. 

In This Article


Characteristics of Patients and Predictive Factors of not Undergoing RNA Testing

Between October 2011 and September 2014, 41 403 HCV antibody tests corresponding to 34 073 subjects were requested. Among these, 870 (2.55%) patients tested positive. We excluded 243 patients with a previous RNA test, 10 positive anti-HCV subjects under 2 years old, 106 patients lost to follow-up, and 88 patients who died during the follow-up period. Finally, 423 patients with a positive anti-HCV test were included in the pre-alert cohort (72.1% male, median 47 years, range 11–86 years).

After follow-up (median 57.0 months; range 45.6-82.1), 159 patients (37.6%) did not have RNA testing (67.9% male, median 47 years, range 12–86). The majority of these patients (79.2%) were evaluated by primary care physicians. In contrast, 45.8% of the positive anti-HCV patients with RNA testing (n = 264, 74.6% male, median 46 years, range 11–84) were evaluated by hospital-based specialists.

Table 1 shows the characteristics of patients with and without RNA testing. There were no significant differences in age, sex, comorbidity, alcohol and drug use, and psychiatric diseases between the groups. However, patients without RNA tests had a greater rate of normal levels of AST and ALT, a lack of social support and were receiving care by primary care physicians. In the multiple logistic regression analysis, the independent predictors for not undergoing RNA testing were primary care serology request (P < 0.001), no history of drug use (P = 0.005) and lack of social support (P = 0.015) as shown in Table 2.

Impact of the Electronic Alert

Figure 2 shows both cohorts of patients evaluated to assess the impact of adding the computerized alert system. In the post-alert cohort, 234 patients (1.37%) tested positive among the 18 976 requested tests for HCV antibodies (17 061 subjects). After excluding patients, we included 179 patients in the post-alert cohort (74.3% male, median 50 years, range 11–92 years).

Figure 2.

Flowchart of patient selection

Patients in the pre-alert cohort were slightly younger (47.1 ± 12.1 vs 50.3 ± 13.9 years, P = 0.004), had higher percentages of patients lacking social support (12.9% vs 3.9%, P = 0.001), psychiatric disease (23.2% vs 13.4%, P = 0.008) and alcohol (48.4% vs 36.7%, P = 0.011) and drug use (51.2% vs 36.7%, P = 0.002). There were no significant differences in sex, physicians requesting serology tests, baseline values of transaminases and comorbidity (Table 3).

After a median of follow-up of 57.0 months (range 45.6-82.1 months) in the pre-alert cohort and 39.4 months (range 33.5-45.6) in the post-alert cohort, the percentage of patients with positive anti-HCV result and subsequent RNA testing increased from 62.4% in the pre-alert cohort to 77.7% in the post-alert cohort (P < 0.001). In addition, the percentage of patients with detectable RNA increased from 35.0% to 47.5% (P = 0.226). In the multiple logistic regression analysis, the incorporation of the alert system was an independent predictor factor for RNA testing (OR 2.041; CI 1.300-3.195, P = 0.002), as shown in Table 4. Other factors were also found to be independent predictors and the alert showed to be similarly effective among subgroups: with drug use (66.8%-80%, P = 0.045) and without drug use (57.7%-75.9%, P = 0.001), with good (64.3%-76.7%, P = 0.004) or lacking social support (50%-100%, P = 0.014) and in primary care (53.2%-68.3%, P = 0.009) or hospital setting (78.6%-89.7%, P = 0.044), and patients with abnormal ALT (72.6%-84%, P = 0.061) compared to normal ALT (55.7%-72%, P = 0.008).

The time period until RNA testing after a positive HCV antibody test was shorter in the post-alert cohort compared with the pre-alert cohort (6.6 ± 10.0 vs 19.1 ± 70.5 months, P = 0.030).

Overall, the group of patients referred that linkage to specialist care (n = 317, 52.7%) compared to the not referred group had a higher percentage of patients with abnormal AST and ALT (46.0% vs 30.8%, P < 0.001; and 54.0% vs 36.8%, P < 0.001, respectively), higher rates of comorbidity (CI ≥ 2 29.7% vs 18.6%, P = 0.002), higher rates of HCV antibody tests being requested by hospital-based specialties (49.2% vs 26.7%, P < 0.001) and better social support (93.3% vs 85.8%, P = 0.003). No differences were found in sex, age, psychiatric disease and alcohol or drug use. Referral and attendance rates to specialist care were 51.1% in the pre-alert cohort and 56.4% in the post-alert cohort (P = 0.132).