This study presents long-term data (up to 12 months post-graduation) from a series of well selected chronic pain patients admitted to a Canadian community-based, comprehensive, one-to-one, interdisciplinary pain management program funded by MOHLTC. The study population consisted of middle age, well-educated chronic pain patients (with female predominance), with a high proportion of employment (full and part time, 42%, Table 6). Physical and mental/ emotional health outcomes showed statistically and clinically significant initial and sustained improvement with GIC (much/very much improved) at discharge, and 6-months and 12 months from pre-treatment levels, of 77%, 58% and 76%, respectively. Additionally, a substantial positive change in social outcomes was noted particularly in patients who were upon entry to the program on disability due to chronic pain conditions, part time workers gaining full time employment, and students who improved their level of schooling (e.g. from part time to full time, high school to university etc.).
The high proportion of chronic pain patients still at work upon admission to our program is due to early referral by primary care physicians triggered by deterioration at the workplace with decreased productivity and increased absenteeism. We believe that our early intervention maintained the ability of these patients to remain at work or increase their work output.
Our attrition rate (22.4%) is consistent with that reported in the literature (17–57%) [7, 10, 22]. There were no differences in demographics and entry scores on physical and mental/ emotional health between those who completed the program and non-completers other than country of birth for foreign born non-completers (potentially reflecting cultural, employment, household obligations, family structure and psychosocial support differences).
The poor completion rate of validated batteries at 6 and 12 months is a well-known phenomenon and has been reported in pragmatic practice-based clinical studies [7, 8, 23]. Despite our repeat attempts to have the patients complete the follow up questionnaires via text, phone call and email reminders, we had a high number of participants who failed to complete the follow up questionnaires (while the vast majority attended follow up medical visits to our centre, hence we were able to retrieve social health outcomes). The low response rate to our validated batteries may possibly skew our long-term results; however, collateral information from the charts regarding social outcomes in 150/158 completers, strongly suggests that long term benefits from the program are maintained by the majority of patients.
The slight drop in the subjective GIC “much/ very much improved” scores at the 6-month period after program termination and subsequent improvement to exit levels at 12 months, has been observed in other programs. While the reduced number of returned questionnaires at 6 and 12 months may have skewed the results, we did review our raw data and realized that depression and anxiety had increased at 6 months (accounting for the GIC drop), consistent with the hypothesis of an “adjustment period”  until skills are consolidated and life goals get reset (at 12 months) with concomitant increase of subjective GIC “much/ very much improved” scores, equal to those observed at exit.
Our IDP program meets all the criteria of a well-functioning interdisciplinary pain program (as per the American Pain Society White Paper: Interdisciplinary Pain Management, 2008), summarized by Stanos  as follows: Shared philosophy, mission, and objectives; Patient and family centered; Providers/therapists work together for common, agreed upon goals; Approach is integrated and interdependent; Mutual respect and open communication exists between providers, often in team meeting format; Communication is frequent, effective, direct, clear, and reciprocal among team members as well as with primary care providers and referral sources; Quality improvement efforts are ongoing from all team members; Approach to clinical care, education, quality improvement, and research is collaborative; and multimodal treatments are employed.
Our thematic analysis (IASP poster 2020)  has shown that the main reasons that patients recommend to others our interdisciplinary pain management program are: (1) support and validation provided by the interdisciplinary team; (2) the acquisition of pain management tools, namely strategies and techniques on a variety of domains (physical, emotional, cognitive, nutritional etc.); and (3) personalized one-to-one management plan to improve overall quality of life alongside pain control.
Our eligibility criteria have evolved over time after we observed during the first months of the program high drop-out rates in patients with severe untreated or poorly treated psychopathology or presence of life crisis (though the latter can still happen in the midst of the program as our data show). Besides absence of psychopathology, patient motivation is a primary driver for admission, judged not through formal questionnaires, but during a detailed 2–2.5 h team assessment, and if required, review by a psychologist before the patient is accepted to the program. Given the high number of foreign-born patients in the non-completer group, we now pay more attention to family obligations and support that may vary based on cultural background. Our eligibility criteria ultimately are very similar to those of Knight et al. .
Existing literature shows considerable variability in interdisciplinary pain management programs in regard to eligibility criteria, program duration, treatment service provision, mode of treatment administration (primarily group and rarely one-to-one, or combination), funding of the services, numbers of treatment hours etc. [7, 9, 22, 23, 25]. However, all programs irrespective of operational model show improvement in physical, mental and/or social health, though the degree and duration of benefits varies.
Deckert et al.  conducted a systematic literature review and summarized all reported outcome domains in 70 studies meeting selection criteria and assessing the effects of multimodal pain treatments (MPT) for chronic pain. There were twelve single outcome domains identified: three for physical health outcomes, e.g. pain, disability and physical function; six for mental/emotional health outcomes, e.g. fear, depressive symptoms, psychological distress, coping, self-efficacy and catastrophizing; and three for social health outcomes, e.g. work ability, sick leave and actual work status. On the other hand, IMMPACT consensus (Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials) includes the following Core Outcome Domains: (1) pain, (2) physical functioning, (3) emotional functioning, (4) participant ratings of improvement and satisfaction with treatment, (5) symptoms and adverse events and (6) participation disposition . However, IMMPACT does not include measurements of the social dimension of the bio-psycho-social approach of MPT (e.g. return to work or work ability), and this partially explains why there is little overlap between IMMPACT domains and outcome domains used in MPT studies .
Clearly our program provides long term outcome data on all three domains (physical, mental/emotional and social health).