A Comparison of Adherence and CD4 Cell Count with Respect to Virologic Failure Among HIV-Infected Adults Under Combination Antiretroviral Therapy (cART) at Felege Hiwot Teaching and Specialized Hospital, Bahir Dar, Ethiopia

Figures & data

Table 1 Characteristic of Patients with Virologic Failure at 1st, 2nd, and 3rd Time Points after Commencement of cART

Characteristics	1st Time Point (n=792)		2nd Time Point (n=740)		3rd Time Point (n=710)
	Virologic Failure (n)	AOR (95% CI)	Virologic Failure (n)	AOR (95% CI)	Virologic Failure (n)	AOR (95% CI)
Residence area (Ref. = Urban)
Rural	180 (55.6%)	1.35 (1.15–1.98)	176 (55%)	1.46 (1.28–1.78)	168 (45.6%)	1.64 (1.24–1.89)
Sex (Ref. = Female)
Male	164 (48.1%)	1.42 (1.05–1.69)	158 (48.3%)	1.53 (1.24–1.76)	148 (40.7%)	1.68 (1.45–1.92)
Ownership of Cell phone (Ref. = Yes)
No	185 (66.4%)	1.42 (1.21–1.68)	162 (51.7%)	1.48 (1.31–1.64)	185 (72%)	1.52 (1.32–1.75)
Marital status (Ref. = living with partner)
Living without partner	180 (62.5%)	1.45 (1.18–1.74)	175 (62.5%)	1.48 (1.29–1.73)	170 (59.3%)	1.52 (1.32–1.73)
Whether the patient disclosed the disease or not (Ref. = Yes)
No	194 (73.4%)	1.38 (1.15–1.59)	180 (66.7%)	1.52 (1.38–1.78)	170 (59.3%)	1.62 (1.45–1.84)
Baseline CD4 cell count >100 cells/mL (Ref. = Yes)
No	165 (50.8%)	1.57 (1.08–1.78)	163 (52.5%)	1.62 (1.45–1.78)	152 (40.1%)	1.74 (1.52–1.93)
Baseline viral load >100,000 copies/mL (Ref. = Yes)
No	178 (60.9%)	1.38 (1.12–1.57)	185 (70.8%)	1.58 (1.34–.82)	190 (76.3%)	1.64 (1.43–1.86)
CD4 cell count drop to baseline or below (Ref. = No)
Yes	175 (58.6%)	1.54 (1.32–1.89)	172 (60%)	1.68 (1.48–1.88)	180 (67.8%)	1.76 (1.49–1.93)
Current adherence level >95% (Ref. = Yes)
No	108 (84.4%)	1.75 (1.53–1.96)	82 (68.3%)	1.78 (1.52–95)	86 (72.9%)	1.82 (1.62–1.99)
Baseline and follow-up CD4 cell count <100 cell/mL (Ref. = No)
Yes	180 (62.5%)	1.62 (1.38–1.84)	170 (58.3%)	1.72 (1.58–192)	180 (67.8%)	1.78 (1.52–1.94)
Adherence level >95% at first month (Ref. = Yes)
No	185 (66.4%)	1.74 (1.62–1.89)	176 (63.3%)	1.62 (1.54–1.75)	170 (59.3%)	1.55 (1.45–1.68)

Abbreviations: AOR, adjusted odd ratio; CI, confidence interval; Ref, reference.

Figure 1 The area under the ROC for CD4 cell count and adherence at the 1st time point.

Figure 2 The area under the ROC for CD4 cell count and adherence at the 2nd time point.

Figure 3 The area under the ROC for CD4 cell count and adherence at the 3rd time point.

Table 2 Test Characteristics for CD4 Cell Count Change in Identifying Patients with Virologic Failure after Commencement of cART Assessed at 1st, 2nd, and 3rd Time Points

Assessment of Time Point	Cut-Off-Point for CD4 Cell Count Change	AUC (95% CI)	p-value	Sensitivity	Specificity	PPV	NPV	% of Virologic Failure Missed
1st time point (n=792)	≥baseline	0.66 (0.55–0.74)	Ref.	0.62	0.91	0.60	0.86	74%
	<100 cells/mL	0.52 (0.48–0.67)	0.074	0.61	0.62	0.62	0.85	36%
	<50 cells/mL	0.63 (0.35–0.72)	0.024	0.49	0.81	0.66	0.76	58%
	<25 cells/mL	0.61 (0.29–0.48)	0.004	0.41	0.90	0.69	0.70	65%
2nd time point (n=740)	≤baseline	0.69 (0.51–0.79)	Ref.	0.67	0.92	0.62	0.82	69%
	<100 cells/mL	0.66 (0.54–0.75)	0.002	0.65	0.91	0.64	0.78	34%
	<50 cells/mL	0.65 (0.35–0.82)	0.025	0.53	0.97	0.45	0.72	56%
	<25 cells/mL	0.63 (0.29–0.48)	<0.001	0.44	0.98	0.75	0.68	62%
3rd time point (n=710)	≤baseline	0.73 (0.65–0.84)	Ref	0.75	0.94	0.68	0.78	62%
	<100 cells/mL	0.71 (0.64–0.82)	0.004	0.74	0.96	0.69	0.67	34%
	<50 cells/mL	0.63 (0.55–0.69)	<0.001	0.57	0.99	0.75	0.91	29%
	<25 cells/mL	0.68 (0.32–0.53)	<0.001	0.48	0.99	0.78	0.86	58%

Abbreviations: AUC, area under the curve; PPV, positive predictive value; NPV, negative predictive value; CI, confidence interval.

Table 3 Test Characteristics of Adherence to cART Level in Identifying Patients with Virologic Failure after Commencement of cART Assessed at 1st, 2nd, and 3rd Time-Points

Assessment Point	Adherence Level	AUC (95% CI)	p-value	Sensitivity	Specificity	PPV	NPV	% of Virologic Failure Missed
1st time point (n=792)	<100%	0.68 (0.57–0.73)	< 0.001	0.81	0.79	0.62	0.89	21%
	<95%	0.67 (0.58–0.75)	0.004	0.73	0.84	0.79	0.87	25%
	<85%	0.58 (0.45–0.64)	Ref.	0.29	0.90	0.86	0.80	65%
2nd time point (n=740)	<100%	0.68 (0.55–0.76)	0.580	0.85	0.73	0.65	0.92	18%
	<95%	0.71 (0.54–0.75)	0.001	0.82	0.75	0.74	0.90	21%
	<85%	0.64 (0.56–0.75)	Ref.	0.62	0.84	0.78	0.76	62%
3rd time point (n=710)	<100%	0.72 (0.58–0.79)	0.076	0.92	0.71	0.74	0.96	15%
	<95%	0.73 (0.67–0.85)	0.003	0.88	0.73	0.78	0.94	18%
	<85%	0.67 (0.58–0.74)	Ref.	0.38	0.82	0.85	0.71	60%

Abbreviations: AUC, area under the curve; CI, confidence interval; PPV, positive predictive value; NPV, negative predictive value.

Table 4 Test Characteristics for CD4 Cell Count Change and Adherence Levels for Identifying Patients with Breakthrough Virologic Failure after First Visiting Time

Criterion for Virologic Failure	AUC (95% CI)	p-value	Sensitivity	Specificity	PPV	NPV	% of Virologic Failure Missed
CD4 ≤ Baseline	0.52 (0.34–0.68)	Ref.	0.13	0.85	0.40	0.85	82%
CD4 reduce to level ≤50%	0.59 (0.43–0.68)	0.082	0.35	0.86	0.37	0.90	76%
CD4 reduce to level ≤40%	0.54 (0.29–0.69)	0.007	0.14	0.96	0.52	0.86	85%
CD4 reduce to level ≤30%	0.49 (0.37–0.56)	0.024	0.31	0.89	0.37	0.89	67%
Adherence level <100%	0.60 (0.38–0.74)	0.081	0.74	0.45	0.19	0.89	34%
Adherence level <95%	0.65 (0.45–0.76)	0.002	0.65	0.64	0.21	0.93	35%
Adherence level <85%	0.60 (0.54–0.73)	0.006	0.19	0.96	0.48	0.86	82%

Abbreviations: AUC, area under the curve; CI, confidence interval; PPV, positive predictive value; NPV, negative predictive value.

Table 5 PPVs of CD4 Cell Count and Adherence Level for Assessment of Virologic Failure at the 1st, 2nd, and 3rd Time Points

Adherence	CD4 Cell Count Change	1st Time Point (n=792)		2nd Time Point (n=740)		3rd Time Point (n=710)
		PPV (95% CI)	% with Virologic Failure Satisfying Criterion (95% CI)	PPV (95% CI)	% with Virologic Failure Satisfying Criterion (95% CI)	PPV (95% CI)	% with Virologic Failure Satisfying Criterion (95% CI)
<50	≤Baseline	0.92 (0.81–0. 95)	14 (11–19)	0.95 (0.83–0.98)	18 (9–24)	0.97 (0.85–0. 99)	24 (18–32)
	≤50	0.85 (0.77–0.92)	32 (23–43)	0.88 (0.77–0.96)	24 (23–38)	0.92 (0.86–0.97)	28 (19–34)
	≤100	0.73 (0.73–0.92)	35 (26–41)	0.85 (0.73–0.92)	27 (16–31)	0.88 (0.77–0.92)	32 (26–39)
<85	≤Baseline	0.86 (0.74–0.91)	18 (12–24)	0.88 (0.74–0.91)	25 (21–38)	0.91 (0.84–0.99)	30 (26–44)
	≤50	0.82 (0.71–0.89)	23 (16–29)	0.85 (0.71–0.89)	28 (25–39)	0.88 (0.79–0.92)	34 (27–41)
	≤100	0.78 (0.75–0.92)	27 (18–36)	0.84 (0.75–0.92)	30 (25–38)	0.88 (0.79–0.96)	38 (29–46)
<95	≤Baseline	0.81 (0.78–0.89)	19 (11–26)	0.85 (0.78–0.95)	22 (11–26)	0.87 (0.78–0.95)	32 (26– 38)
	≤50	0.78 (0.66–0.83)	22 (19–36)	0.80 (0.48–0.93)	25 (19–36)	0.85 (0.68–0.93)	34 (27–40)
	≤100	0.75 (0.69–0.84)	24 (16–31)	0.78 (0.67–0.85)	28 (16, 31)	0.80 (0.71–0.88)	37 (28–43)
=100	≤Baseline	0.74 (0.65–0.86)	24 (21–35)	0.78 (0.78–0.95)	24 (20–35)	0.79 (0.72–0. 85)	33 (27–45)
	≤500	0.67 (0.54–0.74)	27 (21–38)	0.70 (0.44–0.64)	26 (21–31)	0.75 (0.64–0.84)	35 (28–43)
	≤100	0.64 (0.53–0.72)	38 (25–44)	0.67 (0.53–0.75)	28 (19–35)	0.70 (0.63–0.75)	38 (27–46)

Abbreviations: PPV, positive predictive value; CI, confidence interval.

Table 6 NPVs for Combined CD4 Cell Count and Adherence Level for Virologic Failure at the 1st, 2nd, and 3rd Time-Points

Adherence	CD4 Cell Count Change Increased	1st Time-Point (n=792)		2nd Time-Point (n=740)		3rd Time Point (n=710)
		NPV (95% CI)	% with Virologic Failure Satisfying Criterion (95% CI)	NPV (95% CI)	% with Virologic Failure Satisfying Criterion (95% CI)	NPV (95% CI)	% with Virologic Failure Satisfying Criterion (95% CI)
>50	>100	0.92 (0.81–0. 95)	36 (26–49)	0.95 (0.83–0.98)	29 (19–44)	0.97 (0.85–0.99)	24 (18–32)
	>50	0.85 (0.77–0.92)	38 (23–43)	0.88 (0.77–0.96)	28 (23–38)	0.92 (0.86–0.97)	26 (19–34)
	Not decreased	0.73 (0.73–0.92)	40 (26–41)	0.85 (0.73–0.92)	27 (16–31)	0.88 (0.77–0.92)	22 (18–35)
>85	>100	0.86 (0.74–0.91)	38 (18–43)	0.88 (0.74–0.91)	25 (21–38)	0.91 (0.84–0.99)	22 (16–34)
	>50	0.82 (0.71–0.89)	37 (26–45)	0.85 (0.71–0.89)	28 (25–39)	0.88 (0.79–0.92)	24 (21–31)
	Not decreased	0.78 (0.75–0.92)	35 (18–36)	0.84 (0.75–0.92)	30 (25–38)	0.88 (0.79–0.96)	38 (29–46)
>95	>100	0.89 (0.78–0.89)	36 (27–46)	0.93 (0.78–0.99)	32 (11–36)	0.97 (0.78–0.95)	28 (26–38)
	>50	0.88 (0.66–0.83)	35 (23–40)	0.90 (0.48–0.93)	28 (19–36)	0.94 (0.68–0.98)	26 (19–40)
	Not decreased	0.86 (0.76–0.90)	50 (26–67)	0.88 (0.67–0.85)	28 (16–31)	0.90 (0.71–0.98)	27 (23–43)
=100	>100	0.90 (0.75–0.99)	37 (21–35)	0.93 (0.85–0.95)	35 (28–46)	0.96 (0.82–0.98)	33 (27–45)
	>50	0.89 (0.74–0.94)	39 (28–45)	0.92 (0.74–0.96)	38 (31–45)	0.75 (0.69–0.84)	35 (28–43)
	Not decreased	0.88 (0.83–0.93)	55 (45–67)	0.89 (0.85–0.96)	47 (38–54)	0.96 (0.88–0.98)	38 (27–46)

Abbreviations: CI, confidence interval; NPV, negative predictive value.