Results:
Inclusion and exclusion: Of the 2 799 patients
hospitalised during the study period, we excluded 440 for the reasons
described above. Of the 2 359 patients included, we selected those with
a first PCR test result obtained within 48 hours of admission (1 294)
and those who had a PCR within the first ten days of care (1 276)
(Figure 1 ). Of them, 747 were PCR negative within 30 days of
follow-up and 529 were censored at the date of their last positive PCR
during follow-up (Table 1 ).
Comparison of treatment with HCQ versus no HCQ: The
population analysed included 776 people who received hydroxychloroquine
(HCQ) and 500 who did not receive hydroxychloroquine. Patients in the
HCQ-treated group were significantly younger than those in the group not
treated with HCQ, they had a longer time from symptom onset to treatment
onset, and a lower baseline viral load (Table 2 ). It should be
noted (see above) that these three factors were likely to affect viral
clearance in favour to treatment. In the crude analysis, the time from
treatment onset to viral clearance was significantly lower in the HCQ
group than in the untreated group (Log-rank testp <.001) (Table 1 , Figure 2 ). For
example, on D0+5 days, 50.0% (95%CI [46.0%-53.9%]) of patients
in the HCQ group were still positive, compared to 63.2% (95%CI
[58.4%-67.6%]) of patients in the non-HCQ group. At D0+10 days,
23.0% (95%CI [19.0%-27.1%]) of patients in the HCQ group were
still positive, compared to 33.4% (95%CI [27.8%-39.2%]) in the
non-HCQ group (Table 1 ). Overall, the probability of viral
clearance was significantly higher in the group treated with HCQ (Hazard
ratio 95% CI 1.39 [1.20–1.61], p <.0001).
When adjusted for age, initial viral load and time from symptom onset to
treatment onset, which were potential confounding factors, the adjusted
hazard ratio of viral clearance for the HCQ group remained statistically
significant (Hazard ratio 95% CI 1.18 [1.01-1.38], p =.037),
suggesting that the HCQ treatment had a significant impact upon the
probability of viral clearance within 30 days of the onset of treatment
(Table 3 ). We noted a decrease in the probability of
negativization as age increases (Hazard ratios =1, 0.90, 0.72, 0.59, and
0.50 for patients aged <50, 50-59, 60-69, 70-79 and
>79 respectively). When the CT of the first PCR increases
by one unit, the probability of negativization increases by 12% (Hazard
ratio=1.12) i.e. the lower the initial viral load, the greater the
probability of a negative result. Finally, an increased likelihood of
negativization was observed when the time to treatment was longer
(longer time associated with a lower viral load at the time of
treatment).
When treatment with both HCQ and AZT was compared to treatment with AZT
alone, similar results were obtained, suggesting that the essential
element in lowering the viral load is treatment with HCQ
(supplementary data, Figure 1S, Table 1S, Table 2S ). The
sensitivity analysis, using a competitive risk approach (death was
considered a competing event), yielded similar results
(supplementary data, Figure 2S, Table 3S, Table 4S ).