Health-Related Quality of Life in Patients with Primary Immune Thrombocytopenia Compared with the General Population

Recent international guidelines (Rodeghiero F, et al. Blood 113:2386–93, 2009) emphasize the importance of health-related quality of life (HRQOL) in patients with primary immune thrombocytopenia (pITP) and are advocating for more research in this area. However, very little research has been conducted on HRQOL of these patients.

The main objective of this study was to identify specific limitations of HRQOL in pITP patients (ie, chronic, persistent and newly diagnosed patients) in comparison with their peers from the general population. Also, socio-demographic and clinical factors were considered to evaluate HRQOL impairment.

Data were gathered through an ongoing multicenter observational study that recruits p-ITP patients. HRQOL was the primary endpoint of the study and was assessed with Medical Outcomes Study 36-Item Short-Form Health Survey (SF-36) that consists of 36 items covering eight generic health status/QoL domains: physical functioning (PF), role limitations due to physical health (RP), bodily pain (BP), general health perceptions (GH), vitality (VT), social functioning (SF), role limitations due to emotional problems (RE), and mental health (MH). All scales ranging between 0 and 100 with higher scores representing better outcomes. Two summary scores, namely the physical component summary (PCS) and the mental component summary (MCS) are derived from a weighted combination of the eight scales. Mean SF-36 scores were compared to available national general population reference values and analyses were adjusted for age and gender. Based on previous research, eight points were considered to be a minimally important difference (MID) for the first eight SF-36 scales, while a difference of two points was judged as MID for the PCS and the MCS scores. A score difference at least equal to MID was considered as a clinically meaningful difference. Socio-demographic, clinical and laboratory data were also collected to investigate their association with HRQOL outcomes. Univariate and multivariate linear regression analyses were used.

To date of the 256 pITP patients included in this study, 69%, 16% and 15%, were diagnosed with chronic, persistent and newly diagnosed pITP respectively. Present analysis is based on 175 patients with HRQOL data currently available. At study participation, mean age of patients was 54 years (67% female and 33% male). At least one comorbidity was present in 53% of patients. The median time from initial diagnosis to study entry was 0.3, 8 and 77 months respectively for newly diagnosed, persistent and chronic patients. Age and gender adjusted comparisons with general population norms revealed worse outcomes for the following scales: RP (P<.001), GH (P=.01), SF (P=.002), RE (P=.002). The largest clinically meaningful difference (Δ=13.4 points) was found for the RP domain with mean scores of 58.3 vs. 71.7 respectively for pITP patients and the general population. Age specific comparisons, (18–54, 55–64 and >65 years) suggested an almost uniform pattern in all scales with worse outcomes between pITP patients and population controls among the youngest groups. Statistically and clinically meaningful differences (ie, >8 points) were found in five out of the eight scales of the SF-36 in the youngest group of patients (18–54 years), when compared with their peers, while these differences were not present in the other age group categories. Comorbidity was the main factor influencing HRQOL by independently predicting worse HRQOL outcomes across all domains of the SF-36. SF-36 mean score differences in patients with or without comorbidity, were more than twice the magnitude of a clinically meaningful difference for PF and RP, being respectively: 69.7 vs. 87 and 51.3 vs. 68 points.

This study suggests that HRQOL of p-ITP patients is far from optimal. In particular, role limitations (i.e., in work or other daily activities) due to physical health seems the major constraint faced by these patients when compared to their peers in the general population. Comorbidity seems the major factor associated with a poorer HRQOL profile. These findings need to be confirmed with a larger sample size and will eventually help guide the development of patient-centered supportive care programs.

No relevant conflicts of interest to declare.