VERITAS-Pro, originally developed in English, was translated into Brazilian Portuguese according to international translation and adaptation guidelines.13 Two independent translations to Brazilian Portuguese were prepared by native Brazilians. There were no relevant differences between the translations. The two resulting versions were combined, corrected by experts, and translated back into English by an American translator without knowledge of the original document. The Brazilian version has 24 questions divided into six subscales: Time, Dose, Plan, Remember, Skip, and Communicate, just as in the original questionnaire. The questions were written in a way that made it possible for both the individual responsible for the patient's prophylaxis and an observer to respond. The answers are presented as five-point Likert scales ranging from ‘never’ to ‘always’. An ‘always’ response reflects the best possible adherence for some items, and the worst for others. For each item, a numerical classification was assigned to the Likert scale, giving one point to the response representing the best adherence and five points to the worst adherence. Possible scores of each subscale range from 4 to 20 points, and the total score of the instrument, from 24 to 120 points, where 120 represents the worst adherence.

Participants were recruited at the Hemocentro Regional de Juiz de Fora (HRJF) in southeastern Brazil. The individuals considered eligible were those responsible for the prophylaxis of patients with hemophilia with a severe phenotype, A or B, in a home infusion regimen for at least six months. Patients in on-demand treatment, those not qualified to receive home infusions, and those with inhibitors were excluded.

The study was approved beforehand by the Research Ethics Committee of the Fundação Centro de Hematologia e Hemoterapia de Minas Gerais – HEMOMINAS. The participants were asked to respond to the questionnaire during their usual visits to the blood center. All signed a free and informed consent form, allowing access to their infusion logs, and received a guarantee of confidentiality of any individual information. Parents gave their consent to include data from patients under 18 years of age, and adolescent patients (12–17 years old) gave their agreement to participate. Sociodemographic and health data were collected from the patients, as well as sociodemographic data from those responsible for prophylaxis, in the case of under 18-year-old and incapacitated patients. Participants answered a questionnaire and a visual analog scale on global adherence to prophylaxis. For the test–retest evaluation, participants were asked to respond the questionnaire a second time on their next visit to the blood center. Data collection occurred between October 2015 and November 2016.

At the beginning of the study, in October 2015, there were 59 patients eligible for the prophylaxis regimen at the HRJF. Twenty-three patients (39%) had opted to remain on episodic treatment and one tested positive for an inhibitor (1.7%). Of the 36 patients who adhered to the prophylactic treatment, one was receiving the infusions at the blood center and one presented severe clinical complications, requiring frequent changes in the infusion scheme and, for these reasons, they were excluded from the study. Thus, those responsible for the prophylaxis of 34 patients and five observers were recruited for the research, but two patients declined participation. The 32 patients, whose prophylaxis adherence was evaluated, were all males, 27 diagnosed with hemophilia A (21 with factor VIII dosage <1%) and five with hemophilia B (four with factor IX dosage <1%). The patients’ ages ranged from three to 60 years (mean of 20.6 years, with a standard deviation of 14.1). All the boys under the age of six were regularly attending preschool. The patient was responsible for the infusions in only 11 cases (34.3%). Tables 1 and 2 show the sociodemographic and clinical characteristics of the patients, respectively.

The total mean of the VERITAS-Pro was 35.51 (range: 24–70) when the responses of those responsible for prophylaxis and the observers were analyzed together. There was no statistically significant difference when the scores were evaluated separately (35.47 and 35.8, respectively; p-value=0.914). There was also no difference when the patients themselves were the primary infusers (38.91) or others took on this responsibility (33.81; p-value=0.17). The averages of the subscales ranged from 4.59 (Dose) to 7.3 (Time) (Table 3).

Results showed a very good internal consistency for the VERITAS-Pro total score; excellent for the Remember, Skip and Communicate subscales; good for the Dose subscale; and minimally acceptable for the Time and Plan subscales (Table 4).

Twelve participants (37.5%) agreed to answer the VERITAS-Pro questionnaire on more than one occasion for test–retest reliability analysis. The mean interval between the two responses was 55.5 days (standard deviation of 11.9 days; range: 24–145 days). The ICC for the test–retest was excellent for the total score (0.933; p-value <0.01), and for all subscales except for the Plan and Skip domains (Table 5).

The infusion logs of 32 patients were evaluated regarding the 12 weeks that preceded the application of the VERITAS-Pro. In all cases it was not possible to identify prophylactic infusions done outside the schedule of episodic infusions for the treatment of hemorrhagic events. Those responsible reported an average infusion rate of 72.17% of the prophylactic doses prescribed in the period (range: 25–105.5%; standard deviation: 25.8%). Half of those responsible for prophylaxis reported infusion of 80% or more of the prescribed doses, which characterizes good adherence, when this is evaluated dichotomously.7,10,15,16

The global adherence reported by 35 participants (31 responsible for infusions and four observers) through the analog scale ranged from 6 to 10. Mean global adherence was 9.2 with a standard deviation of 1.05 and a median of 10.

The blood center pharmacy usually dispenses doses sufficient for four weeks of prophylaxis on each visit of those responsible for infusions. Thus, the individuals responsible are expected to return with the used bottles at the end of this period and replenish their household supply. The dispensing of doses sufficient for prophylactic infusions in the 12 weeks prior to the survey was analyzed, and the actual time until the return of all used bottles was computed. Adherence was calculated by dividing the number of doses dispensed by the number of doses required to meet the prescription until the return, revealing a mean adherence of 89.02% (standard deviation of 18.3, with a minimum of 45.9% and a maximum of 130%).

Since better adherence is characterized by lower scores on the VERITAS-Pro, higher scores on the visual analog scale, and by higher adherence percentages based on pharmacy dispensing and on infusion logs, negative correlations indicate a stronger correspondence of VERITAS-Pro with other adherence measures. Therefore, VERITAS-Pro scores were moderately correlated with the global adherence scale (r=−0.529; p-value=0.002) and with the records in infusion logs (r=−0.516; p-value=0.003), but showed a weak correlation with the pharmacy dispensing records (r=−0.32; p-value=0.074).