Multimorbidity, the Predominant Predictor of Quality-of-Life, Following Successful Spinal Cord Stimulation for Angina Pectoris

Background: Patients suffering from severe chronic angina pectoris (AP) that has become therapeutically refractory to medication and revascularization can be adequately treated with spinal cord stimulation (SCS). However, following SCS implantation for angina, not all patients show a consistent improvement in quality of life (QoL). Therefore, we sought to study the association of baseline characteristics and chronic multimorbidities on QoL following SCS implantation. Materials and Methods: All patients treated with SCS for refractory AP (rAP) were registered in a local data base. Patients who had discontinued SCS therapy were excluded from further analysis. Baseline characteristics, such as exercise limiting morbidities (chronic obstructive pulmonary disease [COPD], rheumatic disease, diabetes mellitus [DM], obesity expressed as body mass index [BMI] > 25) and demographic data, were retrieved from the data base. QoL was studied using the Seattle Angina Questionnaire and the RAND-36 questionnaire. Results: During a 21-year registration period (1986-2008), we enlisted 127 patients with SCS for rAP in our data base. Eighty-two, of whom 59 died, had discontinued SCS and were lost to follow-up. Out of the remaining 45 patients, 33 returned their questionnaires (73.3%). At SCS implantation, 72.7% of the patients were male, mean age 58 +/- 8.5 years. Twenty-four patients were in class III-IV angina and nine in class II-III NYHA. After a follow-up of 6.4 +/- 4.1 years, men had better physical capacity and experienced less impairment in QoL resulting from physical or emotional restrictions (all p < 0.05) compared with women. Patients without COPD reported a better general health compared with those with rAP and COPD (p < 0.05). The association of DM on QoL was borderline significant. Patients with lower BMI scored better on emotional well-being and perception of disease than those with a higher BMI (p < 0.05 and p < 0.05, respectively). None of the patients reported other morbidities limiting their exercise. Conclusions: Men showed a larger improvement in QoL following SCS implantation, compared with women. As SCS improves rAP, other chronic morbidities such as COPD, DM, and BMI may become the limiting factors for exercise and subsequently adversely affect QoL following implantation of an SCS system. As a consequence of the present relatively small single-center study, we recommend studies regarding rAP and SCS to also address the effect of comorbidities on outcomes.