On-treatment predictions of success in peg-interferon/ribavirin treatment using a novel formula

Table 1 Basic demographic, virological, and clinical features of the 100 patients whose data were used as selection data

	SVR	non-SVR	P value
Number (%)	54 (54.0)	46
Gender (%)
Male	43 (60.6)	28	0.038
Female	9 (34.6)	18
Age
Median	53	57	0.0098
Range	18-72	37-77
Weight (kg)
Median	65.1	60	0.138
Range	42.5-90.5	43.9-86.0
BMI (kg/m2)
Median	23.5	22.9	0.834
Range	17.5-31.8	18.2-31.2
Previous + treatment	22	19	1.000
HCV RNA (KIU/mL)
Median	1889	2263	0.554
Range	140 to < 5000	150 to < 5000
RBC (× 10-4/mL)
Median	469	452	0.0041
Range	319-621	354-552
Hb (g/dL)
Median	15.0	14.1	0.0059
Range	10.9-17.7	11.3-17.2
PLT (× 10-3/mL)
Median	172	159	0.039
Range	84-292	62-270
WBC (/mL)
Median	5000	4850	0.256
Range	3270-8900	2300-9200
NC (/mL)
Median	2550	2549	0.978
Range	1066-4231	1184-5626
AST (IU/L)
Median	54	50	0.898
Range	22-156	24-241
ALT (IU/L)
Median	76	55	0.027
Range	36-311	15-278
PEG-IFN dose (48 wk) (μg/kg per day)
Median	1.43	1.32	0.0043
Range	0.68-1.82	0.52-1.82
RBV dose (48 wk) (mg/kg per day)
Median	10.83	8.39	0.0002
Range	3.42-14.55	2.75-12.64

SVR: Sustained virological response; BMI: Body mass index; RBC: Red blood cell count; Hb: Hemoglobin; PLT: Platelet count; WBC: White blood count; NC: Neutrophil count; AST: Aspartate aminotransferase; ALT: Alanine aminotransferase; PEG-IFN dose (48 wk): Total dose of PEG-IFN at 48 wk (μg/kg per wk); RBV dose (48 wk): Total dose of RBV at 48 wk (mg/kg per day).

Table 2 Logistic regression analysis of independent predictive factors for sustained virological response

Variables	Odds ratio	95% CI	P value
At pretreatment
RBC (× 104) (0 wk)	1.011	1.002-1.021	0.024
PLT (× 103) (0 wk)	1.085	0.986-1.193	0.095
log (ALT 0 wk)	3.509	0.727-16.934	0.118
At week 4
Age	0.941	0.885-1.000	0.051
log (ALT 0 wk)	27.090	1.891-388.001	0.015
RVR +/-	6.543	1.766-24.243	0.0049
log (AST 0 wk)	0.036	0.001-0.886	0.042
At week 12
log (ALT 0 wk)	39.331	2.648-584.144	0.0076
RVR +/-	3.015	0.694-13.100	0.141
EVR +/-	8.340	1.728-40.265	0.0083
WBC (4 wk)	1.001	1.000-1.002	0.035
log (AST 12 wk)	0.049	0.002-1.037	0.053
RBV dose (12 wk)	1.519	1.010-2.284	0.045
At week 24
log (ALT 0 wk)	68.688	3.669 to < 999.999	0.0047
RVR +/-	3.329	0.819-13.529	0.093
EVR +/-	31.775	2.840-355.460	0.0050
WBC (4 wk)	1.001	1.000-1.002	0.044
log (AST 12 wk)	0.036	0.001-0.918	0.044
RBV dose (12 wk)	1.607	1.021-2.528	0.040

Table 3 The median predictive values for sustained virological response (SVR) rates calculated using our formulae at pretreatment and weeks 4, 12 and 24

Median (range)	Patients who attained SVR	Patients with non-SVR	P value
Pretreatment	0.545 (0.286-0.926)	0.507 (0.108-0.945)	0.514
At week 4	0.661 (0.139-0.998)	0.251 (0.056-0.688)	0.000
At week 12	0.589 (0.079-0.994)	0.146 (0.001-0.952)	0.000
At week 24	0.656 (0.038-0.996)	0.026 (0.000-0.949)	0.000

The values were compared between patients who attained SVR and those who did not.

Table 4 Positive and negative predictive values calculated by the formula constructed with data at week 48

Cut-off point	PPV (%)	NPV (%)	P value
0.2	65.9	100	< 0.00001
0.3	66.7	96.7	< 0.00001
0.4	66.7	86.1	< 0.00001
0.5	68.8	82.5	0.000013
0.6	71.4	79.5	0.000024
0.7	77.3	76.0	0.000048
0.8	80.0	70.2	0.00074

The calculated value was applied to the cut-off points and the numbers of patients with sustained virological response were evaluated.