Page 65 - Haematologica-April 2018

MPN patients’ non-adherence to treatment
study in 20.6% (48/233) and 28.3% (15/53); or phenotypic evolution in 12% (28/233) and 17% (9/53), respectively.
At the time of being administered the questionnaire, the patients’ median age was 69.8 years old (range, 26-98.4) and the median follow-up since diagnosis had been 8.3 years (range, 0.5-36.9). In group 1, 163/233 patients (70%) took hydroxycarbamide with a median number of 10.7 pills per week whereas all patients but one in group 2 were receiving injections of pegylated interferon-α2a, in most cases every 3 weeks. Ongoing treatment was the first-line therapy in 72.3% and 22.6% of patients in groups 1 and 2, respectively. Antithrombotic drugs were administered to 217/233 patients (93.1%) of group 1 (78.3% low-dose aspirin) and 48/53 patients (90.6%) in group 2 (68.8% low-dose aspirin).
Characteristics of treatment non-adherent patients
Using the criteria of non-adherence defined in the Methods section (missing at least 3 doses in the preceding month for oral drugs or 1 injection in the 2 preceding months for subcutaneous drugs), 65/286 patients (22.7%) were considered non-adherent to their cytoreductive drug therapy. Non-adherence was more frequent in the orally treated group (group 1) than in the subcutaneously treated group (group 2): 55/233 (23.6%) and 10/53 (18.9%) in groups 1 and 2, respectively, P=0.46). All the characteris- tics are showed in Table 2.
Regarding compliance with antithrombotic drug thera- py, 46/286 patients (16.1%) in the whole cohort declared that they did not adhere fully to their treatment. The patients in group 2 declared a higher rate of non-adher- ence to their antithrombotic drugs compared to the patients in group 1 [13/53 (27.1%) versus 33/233 (15.2%), respectively, P=0.055]. In both groups, patients who were non-adherent to their cytoreductive drug treatment were also less adherent to their antithrombotic therapy com- pared to patients who were adherent to their cytoreduc- tive drug treatment [26/65 (40%) versus 20/221 (9%), P<10- 7; ORR=6.64, 95% CI: 3.22-13.94].
In total, 85/286 patients (29.7%) were non-adherent to either cytoreduction or antithrombotic drugs and 27/286 to both treatments (9.4% of the total cohort or 31.8% of the non-adherent patients).
In both groups, the number of treatment omissions was close to the threshold defining non-adherence (around 10% of intake omissions) for most patients (96%) while the remaining 4% had very poor adherence to treatment (≥20%).
Analysis of the cohort
To tease out the characteristics of treatment non-adher- ent patients, we then analyzed the responses of these patients to cytoreductive drugs (n=65).
In the whole cohort, non-adherent patients were younger (68.1 versus 70.7 years, P=0.007), more frequently male (1.1 versus 0.66, P=0.07), taller (172 versus 165 cm, P=0.004) and heavier (74 versus 69 kg, P=0.01). The differ- ences in height and weight were probably not only due to the gender bias because treatment non-adherent patients remained significantly taller even when only male patients were analyzed, (176 versus 173, P=0.002). This was not true for female patients. Furthermore, in the treatment non-adherent group there was a higher proportion of patients choosing their own drug intake schedule (55.4 versus 34.8%, P=0.003), a lower proportion of patients fol- lowing a fixed intake schedule (64.6 versus 83.7%, P=0.0008) and fewer polymedicated patients (67.7 versus 79.2%, P=0.05). Interestingly, diabetic patients were sig- nificantly more adherent to their cytoreductive treatment [21/221 (9%) versus 1/65 (1.53), P=0.03; ORR=6.69, 95% CI: 1.03-281.86].
Since groups 1 and 2 had different rates of compliance, we analyzed the characteristics of the treatment non- adherent patients for each group.
In group 1, treatment non-adherent patients were younger than adherent patients (66.6 versus 73.4 years old; P=0.0013), more frequently determined the pill intake schedule themselves (52.8% versus 33.7%; P=0.029), dis- persed their pill intake through the day instead of group- ing the pills together (30.9% versus 10.8%; P=0.0003) and had fewer drugs to take (70.9% versus 82.5%; P=0.06). For group 2 patients, the only significant difference concerned
Incidence of non-adherence
Table 1. Characteristics of the population studied.
Characteristics
Number of patients
Age at the time of consultation (y) Sex ratio
Pathologies (ET/PV)
On-going treatment (n/%) Hydroxycarbamide Anagrelide
Pipobroman
Ruxolitinib
Pegulated interferon α2a
Pegulated interferon α2b
Low dose aspirin
Vitamin-K antagonists
Clopidogrel
Associations of antithrombotic drugs
History of thrombotic events
before diagnosis (n./%)
Cardiovascular risk factors (n/%) High blood pressure Hypercholesterolemia
Tobacco use
Cohort
286
69.8
1.34 150/136
163 (57) 37 (12.9) 24 (8.4) 9 (3.1) 52 (18.2) 1 (0.4) 194 (72.9) 43 (16.2) 18 (6.8) 9 (3.4)
84 (29.4)
131 (45.8) 61 (21.3) 26 (9.1) 22 (7.7)
Group 1 Oral drugs
233
72.4 1.4 128/105
163 (70) 37 (16) 24 (10) 9 (4) na
na 163 (74.8) 32 (14.7) 16 (7.3) 7 (3.2)
74 (31.8)
112 (48) 53 (22.8) 20 (8.6) 20 (8.6)
7.6
48 (20.6) 28 (12)
1.8
32 (13.7)
16 (6.9) 7 (3) 17 (7.3)
55 (23.6) 33 (15.2) 22 (9.4) 67 (28.8)
Group 2 SC drugs
53
61.2 1.12 22/31
na
na
na
na
52 (98,1) 1 (1,9) 31 (64.6) 11 (22.9) 2 (4.2)
2 (4.2)
10 (18.9)
19 (35.8) 8 (15.1) 6 (11.3) 2 (3.7)
11.9
15 (28.3) 9 (17)
1.8
3 (5.7)
2 (3.8) 1 (1.9) 0
10 (18.9) 13 (27.1) 5 (9.4) 18 (34)
Diabetes
Median follow-up before consultation (y)
Patients with complications from diagnosis to consultation (n/%)
8.3
Thromboses Hematologic evolutions
Median follow-up from consultation (y)
Patients with complications after completion of questionnaire(n/%)
Thromboses Hematologic evolutions Death
Non-adherence analyses (n%) Cytoreductive drugs Antithrombotic drugs
Both
Total
63 (22) 37 (12.9)
1.8
35 (12.3)
18 (6.3) 8 (2.8) 17 (5.9)
65 (22.7) 46 (18) 27 (9.4) 85 (29.7)
ET: essential thrombocythemia; na: non-applicable; n: number; PV: polycythemia vera; SC: subcu- taneous; y: years; %: percent.
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