Our laboratory has received a total of 3102 blood samples, corresponding to 1765 different individuals seropositive for anti-HCV between January 2010 and October 2016 previously diagnosed through rapid tests in health care structures (see Tables 1 and 2 for details). A large majority of patients (n = 1233; 70%) had a single viral load measurement, while 220 (12%) had two, 129 (7.3%) had three VL tested and the others more than 3 (one patient had been tested 18 times). At the beginning of the activity of CILM in 2010, only 44 patients were received annually (Fig. 1). Then the number of patients increased to 378 in 2015 and the number of collected samples was about 2 times greater. Since 2013 the number of patients and samples have been almost stable.
Table 1. Global results on the whole group and sub-groups.
Table 2. Compared characteristics of the whole group of patients and HCV RNA ∓ sub-groups.
The 1765 patients who presented at the CILM for VL measurement were sub-divided into 3 sub-groups: true positive (the largest group with 1278 people), true negative treated and not treated (487) and true negative not treated (407). The sex-ratio of the whole group of patients (and also of true positive and true negative non-treated) was 1.2. The age ranged from 13 to 86 years, with median ages of 53.8 for men and 51.6 years for women (P = 0.006). Patients with an on-going infection (true positive) were displaying higher median values for aminotransferases (P < 0.0001) than negative patients. A subset of 407 naive patients (28.4%) were negative for HCV RNA (called "true negative and non-treated" in Table 1). These naïve patients could reflect the natural course of HCV infection in Lao populations with spontaneous cleared infection (if any). However, among this sub-group, 42 benefited from a second VL measurement and 7 (16.7%) of them turned out to have VL > 50 IU/mL suggesting that HCV loads were possibly oscillating around detection threshold in a sizable proportion of patients. Individuals with apparent spontaneous recovery at initial sampling were significantly younger than RNA(+) patients (48.4 ± 12.7 vs. 52.4 ± 11.3; P < 0.0001). No gender difference was noticed in this sub-group. Remarkably, despite the absence of circulating HCV genomes, 41.0% (n = 52) of HCV RNA(-) subjects tested for aminotransferases displayed levels above the upper limit of normal.
Treatment prescription reflected the availability of drugs in Laos and economic status of the patients; as a result, international guidelines were seldom followed by the prescribing physicians.
Ten drugs were used in mono to quadruple therapy (Table 3). In total, 329 patients (18.7% of the whole group) received an antiviral treatment including a subset of 80 (24.4%) subjects negative for HCV RNA(-) who were receiving or had already received antiviral treatment at the time of initial VL determination (Tables 1 and 2). We then compared treated individuals (those with confirmed presence of the virus), who had been cured of the virus with those patients who remained chronically infected. Gender distribution was somewhat skewed towards men in patients who displayed a sustained viral response to treatment, albeit without reaching the level of significance (P = 0.0906, ns). As for untreated patients, disappearance of HCV RNA in treated patients was the characteristic of younger age (49.8 ± 11.1 vs. 52.6 ± 9.3, P = 0.031).
Table 3. Percentages of drugs used in mono, multi therapy and all together.
The De Ritis ratio (AST/ALT ratio) was similar in RNA(+) and RNA(-) groups with 38% of the latter displaying a value above 1.1, indicative of significant liver fibrosis.
When we considered treatments received, we observed that patients who had recovered from viral infection received Pegylated interferon significantly more often than other drugs.
Among infected patients, VLs were significantly higher in treated than in naive patients (6.4 ± 1.7 vs. 5.4 ± 1.3, P < 0.0001). Furthermore, an important subset (64.3%) of treated patients had VL > 6 log10, a threshold considered by some Asian authors as a predictor for liver disease progression (Noh et al. 2016). This rate was significantly lower in treated naive patients (31.8%, P < 0.0001). Concerning liver damage, treated patients displayed decreased enzyme values when compared with untreated ones.
Among the 249 HCV RNA(+) treated patients (detailed in Table 2), 108 have AST and 104 have ALT measurements; 65 patients were treated before aminotransferases determination and 39 were treated subsequently. AST and ALT medians were significantly lower (respectively P = 0.005 and P = 0.026) when the treatment was received before transaminases evaluation. Among the 39 patients treated after the first transaminase sampling, 17 had a second determination after treatment. Only the AST median was significantly lower after treatment (P = 0.014). However, time intervals between samplings were extremely variable and this group rather small. A group of 197 infected treated patients had 2 serial VL determinations (data not shown). We observed in them a significant decrease of the mean and median VL (P < 0.0001), but there was no difference between therapeutic schemes regarding the magnitude of VL decrease.
58% of this group received monotherapy with acridoneacetic acid (Cycloferon) predominantly employed. Therefore we compared Cycloferon impact on VL in patients who received it in mono or dual therapies (Table 4). We noticed that the viral response to Cycloferon was stronger when monotherapy was used (P = 0.0001).
Table 4. Comparison of the medians of VL at first sampling (1) and second sampling (2) in true positive treated patients with (+) or without (-) cycloferon in monotherapy versus dual therapy.
We also analysed the impact of dual therapy on true positive patients with 2 samplings. A subset of 88 patients received dual therapy: 31 ribavirin + Cycloferon (group 1), 30 ribavirin + Pegasys (group 2) and 27 "others" (group 3). We found that VL were more strongly impacted in group 2, while groups 1 and 3 were similar (same decrease of the VL) P < 0.0001).
The global impact of monotherapy versus dual therapy on VL was also assessed. We observed that there was no difference between these therapeutic schemes regarding viral response.
As shown in Fig. 2, 10 different medicines were used between January 2010 and November 2016. The drug classes included adenosine analogues (adefovir and tenofovir), guanosine analogue (ribavirin), cytidine analogue (lamivudine), immunostimulant (cycloferon), and Interferon-like (Interferon, Pegasys), NS5A replication complex inhibitors (ledipasvir, daclatasvir) and nucleoside NS5B polymerase inhibitors (sofosbuvir). Ribavirin, cycloferon and pegasys were the most prescribed drugs; they peaked in 2012, 2014 and 2015 respectively. The least used drug was sofosbuvir.