Table 4.
Characteristics of LPV/r resistance versus no LPV/r resistance
| Patient Characteristics | No LPV/r resistance (n = 406) | LPV/r resistance (n = 138) | Univariate | Multivariate | ||
|---|---|---|---|---|---|---|
| OR [IQR] | p‐value | aOR [IQR] | p‐value | |||
| Sex (% female) | 59.1% (240) | 57.2% (79) | 0.93 [0.63 to 1.37] | 0.78 | 1.03 [0.68 to 1.56] | 0.89 |
| Age (years) | 40.4 [31.2 to 48.1] | 42.7 [37.0 to 50.7] | 1.19 [1.09 to 1.30] | <0.001 | 1.21 [1.10 to 1.32] | <0.001 |
| Log HIV‐RNA at second‐line failure (log copies/mL) | 4.9 [4.3 to 5.4] | 4.9 [4.5 to 5.4] | 1.18 [0.93 to 1.51] | 0.28 | 1.23 [0.95 to 1.59] | 0.11 |
| Second‐line NRTI backbone | ||||||
| AZT/3TC | 60.3% (245) | 67.4% (93) | Ref | Ref | ||
| TDF/3TC | 18.7% (76) | 19.6% (27) | 0.94 [0.56 to 1.53] | 0.80 | 0.97 [0.57 to 1.61] | 0.91 |
| ABC/3TC | 14.8% (60) | 10.9% (15) | 0.66 [0.35 to 1.19] | 0.18 | 0.65 [0.33 to 1.19] | 0.17 |
| Other | 6.2% (25) | 2.2% (3) | 0.32 [0.07 to 0.93] | 0.06 | 0.32 [0.07 to 0.94] | 0.07 |
| Time since ART start (months) | 64.9 [39.9 to 81.0] | 105.9 [67.3‐ to 137.3] | 1.02 [1.00 to 1.05] | 0.14 | NA | NA |
| Time since start second‐line ART (months) | 30.8 [16.2 to 51.7] | 64.4 [36.2 to 75.7] | 1.04 [1.00 to 1.08] | 0.05 | NA | NA |
| CD4‐count at start ART (cells/mm3) | 85 [47 to 190] | 38 [33 to 115] | 0.83 [0.31 to 1.18] | 0.54 | NA | NA |
| CD4‐count at start second‐line ART (cells/mm3) | 192 [75.333] | 327 [288 to 393] | 1.14 [0.91 to 1.41] | 0.05 | NA | NA |
Results displayed as percentage (count) or median [interquartile range]. Time on treatment and CD4‐count were not assessed in the plasma group. OR for differences calculated using χ2‐test for categorical variables and Mann‐Whitney Wilcoxon for continuous variables. aOR for LPV/r resistance was calculating using multivariable logistic regression, entering sex (reference = male), age (per five years increment), log HIV‐RNA (per 1 log increment), and NRTI‐backbone (reference = AZT/3TC) as covariables and correcting for sampling group (DBS vs plasma). Time on treatment was assessed in months and CD4‐count in increments of 50 cells/mm3. These variables were only available for patients in the DBS group and therefore not entered in multivariable analysis. 3TC, lamivudine; ART, Antiretroviral treatment; ABC, abacavir; aOR, adjusted Odds Ratio; AZT, zidovudine; CD4‐count, CD4+ T‐lymphocyte count; DBS, Dried Blood Spot; IQR, interquartile range; LPV/r, ritonavir‐boosted lopinavir; NRTI, nucleos(t)ide reverse transcriptase inhibitor; TDF, tenofovir disoproxil fumarate.