Pathways of healthcare utilisation in patients with suspected adolescent idiopathic scoliosis: a cross-sectional study

Conceptual framework

The conceptual framework for studying the relationships between user (child and family) and system characteristics, primary healthcare utilisation (healthcare pathways), and outcomes (appropriateness of referral to a specialised orthopaedic clinic) is derived from Andersen’s Behavioral Model of Health Services Use [23–25] and is presented in Fig. 1.

This well validated and largely used model was chosen because it proposes an explanatory process and a logic organisation of the determinants of healthcare use. Considering the two objectives of the study, it is an appropriate choice of framework. It allows taking into account all relevant factors in order to characterise the pathways (objective 1). Indeed, it views access to services as a result of decisions made by an individual (and family), which are constrained by the social environment, and the availability of healthcare services [26]. It allows the investigation of the relationships between prior use and current patterns of health care services utilisation (objective 2).

In this model, predisposing, enabling, and need factors contribute to the individual’s health utilisation behaviour. Predisposing factors exist before the perception of morbidity and include demographic and social structural variables [27]. Enabling factors are individual or situational characteristics that facilitate or impede the utilisation of health services, such as individual and familial resources, as well as availability and accessibility of health services in a community [23–27]. Need factors are divided into two conceptual categories within our framework: those pertaining to the signs and symptoms of a health problem are labelled as perceived morbidity, and those referring to professional evaluation of the disease and primary healthcare utilisation, as objective morbidity. The latter is studied in relation to outcome, adjusting for predisposing, enabling, and perceived morbidity factors, as these may change the original relationships.

Study design and population

We conducted a cross-sectional study with all children aged between 10 and 18 years, and their accompanying parent (guardian), referred for an initial visit for suspected scoliosis in all five out-patient paediatric orthopaedic clinics of south-western Quebec (Canada) between February 2006 and August 2007. The study concerns five out of the six paediatric orthopaedic clinics in the province of Québec (a Canadian province of 7.5 million inhabitants). Therefore, it represents approximately 70 % of all patients seen in paediatric orthopaedic clinics in Québec. The population served by these clinics is ethnically and socioeconomically heterogeneous and comes from diverse regions (metropolitan, urban and rural areas) of the province. Quebec is a province without school screening or any specific intervention program for early scoliosis detection. Quebec’s health system is universal, with consultation in primary and specialised care fully covered by the government. A request by a referring physician is usually required to access specialised care. However, self-referral still occasionally occurred at participating clinics, which did not systematically require a referral letter when scheduling an appointment.

Data collection

The research protocol and the questionnaires satisfied the ethical requirements of the institutional review boards of all the participating hospitals and institutions (Sainte-Justine University Health Centre, Shriners Hospital for Children, McGill University Health Centre, McGill University Faculty of Medicine, University of Sherbrooke Health Centre, and Children Hospital of Eastern Ontario). Newly referred patients at the spine clinics were identified from scheduled appointment lists. Children and accompanying parents were informed of the details of the research protocol, including voluntary participation and the protocol’s risks and benefits, by a research nurse or assistant. They were given adequate time to ask questions and review the information. If they agreed to participate, they were invited to sign a consent (assent) form and were given the questionnaires in a room adjacent to the clinic. Questionnaires were consistently administered before radiographic and medical examination to blind the interviewer to the outcome and prevent changes in the respondents’ disease perception.

Children were instructed to complete a self-administered questionnaire on their health perception, back signs, symptoms, and life habits. Their accompanying parent was first asked to participate in a face-to-face interview with a trained research assistant to document the detailed circumstances of healthcare use for their child’s back problem prior to the orthopaedic consultation. In addition, the parent completed a self-administered questionnaire focusing on family demographic and socio-economic characteristics as well as on the parent’s health-related attitudes, behaviours, and knowledge. Mean duration for questionnaire completion was 30 min. In some cases where time constraints impeded completion of questionnaires, permission was requested to access the respondent’s clinical record, to assess the possibility of a selection bias. All questionnaires were available in French and English, according to the participants’ preferences. All data were stored in a dedicated Access database (Microsoft Corp.), using unique numerical identifiers for confidentiality.

Study variables

The main outcome in this study, appropriateness of referral, which determines orthopaedics utilisation, was assessed by comparing the child’s back condition at the time of referral with defined criteria of appropriateness [13] based on expert opinions, known risk factors for scoliosis progression [28–31], treatment indications [32–35], and published guidelines for the management of scoliosis patients [36–39]. Generally speaking, patients who should receive particular attention from an orthopaedist are those presenting a clinically significant scoliosis (as measured by the Cobb angle) and a residual growth potential (Risser sign) [40–45]. Therefore, the outcome was defined as a nominal variable consisting of three mutually exclusive categories: appropriate referral, inappropriate referral, and late referral. Appropriate referrals were those respecting the Scoliosis Research Society’s diagnostic criteria: lateral deviation of the spine above 10 degrees, without inherited disorders of connective tissue, neurological disorders, or other musculoskeletal disorders [36, 37], and where the referral was not late. Late referrals occur when skeletal maturity and curve magnitude at the initial visit in orthopaedics are beyond the indications for brace treatment (suggesting the need for surgical management) or are less likely to respond to treatment [29, 32, 34, 37, 46]. Therefore, patients presenting with a Cobb angle greater than 40°, regardless of skeletal maturity, and immature patients (Risser sign of 0, 1, 2, or 3) with a Cobb angle greater than 30° were all considered late referrals. Inappropriate referrals were those patients with curve magnitude below the diagnostic criteria, i.e., 10 degrees or less.

The main independent variables that characterise healthcare pathways are defined by five steps, which are nominal variables documenting primary healthcare utilisation prior to the orthopaedic consultation.

For each of these steps, parents were asked for the names and office locations of the professionals they had seen. We subsequently verified the accuracy of respondents’ categorisation by confirming the specialty of each named professional in the records of Quebec’s medical and professional associations (names were subsequently discarded to preserve confidentiality). The parents also provided approximate dates of visits, using a calendar to determine the sequence of events.

Other variables in the conceptual framework are described below.

Data analysis

To address the first objective, characterisation of the healthcare pathway, we defined a taxonomy [47]. To achieve this, we first investigated relationships between the categories of the five nominal variables representing healthcare pathway steps, using multiple correspondence analysis (MCA), a form of factorial analysis. One hundred and sixty-six different combinations of pathway steps were empirically observed in our study sample. Use of MCA resulted in data simplification and noise reduction, by searching for common attributes of the observed data, without significant loss of information. Using this technique, a lower-dimension factor subspace was identified, accounting for most of the variance in the data. Participants were thereafter represented by their coordinates on the factorial axes. The decision on the number of factorial axes to retain for subsequent analyses was based on the elbow criterion applied to the eigenvalue curve [48–50], and on the cumulative inertia (adjusted eigenvalues with the Benzécri correction for MCA) [51].

We then used ascending hierarchical classification (AHC) to establish a taxonomy of the pathways, by grouping the participants [52] based on the common characteristics of their pathway steps (similar positioning on the factorial axes). This group partitioning technique involves minimising intra-class variance and maximising inter-class variance. The classification algorithm consisted in grouping together the two individuals closest in space, then iteratively merging the two closest groups of individuals (according to the Ward distance) until all the data were merged into a single class. Each level of the resulting tree was a possible segmentation of the data. The decision on the number of classes to be retained was based on computed change in inter-class inertia (a measure of variability that we wished to maximise) going from n to n-1 class configurations, as well as on the theoretical plausibility, interpretability, and stability of the solution [48]. The final set of classes was considered to represent the taxonomy of pathways and a name was attributed to each class.

In MCA and AHC, supplementary variables (predisposing, enabling, and perceived morbidity factors) from the conceptual framework are not used to compute the factorial axes nor for classification. However, they are useful to the interpretation of results [49]. As such, supplementary variables significantly associated with the classes were used to describe patient profiles within each class.

For the second objective (associations between healthcare pathways and appropriateness of referral), the categories of the newly defined pathway taxonomy were cross-tabulated with the appropriateness of referral status. In addition, adjusted multinomial logistic regression models of these associations were built from operator-specified hierarchical variable blocks involving the previously mentioned predisposing, enabling, and perceived morbidity factors. We presented the most parsimonious model retaining the variables that had a substantial impact on the odds ratios (using a percentage of excess risk of 10 %) [53].

Analyses were carried out with SPAD 7.4 (Système Pour l’Analyse des Données, Coheris, France) and IBM SPSS Statistics version 20.

Sample characteristics

Of the 930 consecutive eligible children seen in the five participating clinics, 831 completed the study with their accompanying parent, for a participation rate of 89 %. Only 13 eligible families refused to participate. Another 86 eligible children/parents did not complete the questionnaires due to time constraints at the clinic. Therefore, their pathways were not characterized. But since they granted access to their clinical data, we assessed the possibility of selection bias. In fact, they did not differ from the full participants on distribution of available data: appropriateness of referral (main outcome), age, gender, or access to a regular source of care. The study sample (n = 831) consisted of 599 girls and 232 boys with a mean age of 13.9 ± 1.9 years. Sixty-three per cent of participants reported having access to a regular source of care, but 31 % declared they had never heard of scoliosis before the initial orthopaedic consultation. The great majority of the children’s mothers had at least a high-school level of education and were born in Canada. Most families resided outside the administrative regions where the orthopaedic clinics were located and in regions where the density of healthcare resources is below average.

There were 517 (62.2 %) children with confirmed AIS, mostly double and thoracolumbar curves with mean Cobb of 26.2 ± 13.3 [11°–91°]. Of these 517 children with AIS, 147 (17.7 % of total sample) were considered late referrals. The remaining 314 children (37.8 % of the total sample) did not meet the diagnosis criteria and were considered to have been inappropriately referred to orthopaedics.

Healthcare pathway taxonomy

Two factorial axes were retained for the MCA, accounting for 85.1 % of the total inertia in the data [51]. The solution showed that two pathway steps were chiefly responsible for differentiating the participants. The first axis was clearly defined by circumstances of ‘scoliosis suspicion’, from ‘suspicion by the regular source of care’ and ‘other medical doctor’ to ‘lay suspicion’ and ‘other professional’. The ‘referral visit’ step was the main contributor to the second axis, ‘same as first consultation’ and ‘other specialist’ to ‘regular source of care’ and ‘self-referral’. The hierarchical classification algorithm led to a five-class solution; no significant gain in inertia ratio was obtained for less parsimonious solutions. Table 1 presents the pathway class composition and shows percentages of participants presenting a given variable category for each class.

The pathway obtained from Class 1 (termed ‘Lay/regular source of care interrelation’) illustrated the complementary roles of the ‘layperson’ and the ‘regular source of care’ variables. Suspicion was mainly attributable to ‘laypersons’ (or ‘other professionals’), the first medical consultation and the referral visit were mainly conducted with the regular source of care (or never occurred), and ‘no test’ was the most common category for the diagnostic tests. The category ‘somewhat serious’ for the parent’s perception of seriousness is related to this class. The Class 2 pathway (termed ‘Other professionals’) illustrated the effect of relying on ‘other professionals’ for suspicion, referral, and other consultation. Only 72 participants belonged to this class. The Class 3 pathway (termed ‘Lay/consultation discontinuity’) described circumstances where lay suspicion led to a first medical consultation and referral by other medical doctors and consultations with several other professionals, in the absence of a regular source of care. Child’s and parent’s perceptions of the back problem as serious and urgent at the time of suspicion were significantly associated with this class. Also represented in this class were patients in the oldest age category, patients who did not live with both parents or with their mother, patients who did not practice any instructed sports, and patients living outside of the administrative areas where the orthopaedic clinics were located. The Class 4 (termed ‘Other MD’) pathway seemed to account for the particular case of suspicion by a medical doctor not involved as the child’s regular source of care. Many of these children were on medication for other health problems; therefore scoliosis detection may have occurred as an incidental finding in the course of other treatment. This class consisted of only a few patients. Finally, the Class 5 pathway (termed ‘Regular source of care continuity’) represented complete management by the regular source of care. The regular source of care (or other MD in some cases) was responsible for the scoliosis detection and ensured consultation and referral. The most common category for ‘other consultation’ was ‘none’, and ‘bending’ was the most frequent for ‘tests’. Patients younger than the sample mean age who visited the medium-sized clinic were represented in this class.

Methodological strengths and limitations

Although a cross-sectional design was used for this study, the temporal sequence of events allowed for logical inferences. Nevertheless, the participants’ perception of morbidity may have changed between the time of suspicion or detection and the referral visit (when it is measured), depending on the nature of their experiences along the healthcare pathway.

The milestones of the healthcare pathway were determined from self-reported information. This type of data, which is usually considered valid, is much more informative than relying on administrative data. While there is potential for recall problems, especially in participants reporting a complex history of healthcare use, we have no reason to suspect the presence of any specific pattern of modification in the responses. Similarly, although social desirability bias could not be ruled out in parental reporting of the initial notification of the scoliosis signs, precautions were taken (by controlling the order of questions, interview approach, etc.) to elicit unbiased collaboration from respondents.

We used multiple correspondence analysis in conjunction with hierarchical classification, an approach to studying interrelationships between categorical variables that is gaining popularity in epidemiology and public health research areas. Here it makes an important conceptual contribution to the field of healthcare utilisation for scoliosis, since it allows a holistic view of the phenomenon, which the study of the individual pathway steps would not have provided. The interpretability and robustness of the solutions, as confirmed by sensitivity analysis, supported our decisions regarding number of factors and chosen classes.

The criteria and cut-off values used to define the outcome categories (appropriate, late and inappropriate referral) were defined from expert opinions based on diagnostic criteria, known risk factors of curve progression and published indications for treatment [20, 21, 28–39]. In absence of guidelines for scoliosis referral, the practice and opinions may vary; therefore, cut-off values of the chosen categories could be discussed. No detailed sensitivity studies were conducted on our regression models to assess this, but a few scenarios were tested without significant impact on the results of such “misclassification” (e.g. classification of mature patients with mild curves in the inappropriate category or moving the cut-off value for the appropriate category to 15 degrees Cobb angle).

The proportions of inappropriate, late, and appropriate referrals in this study were identical to those previously reported for the same geographical area [13]. These findings suggest the possible impacts of having discontinued school scoliosis screening programs and of relying on familial and systemic awareness for scoliosis detection. Indeed, the current case-mix clearly differs from what was observed during the time of school scoliosis screening programs in Quebec [2, 3]. Similarly, Ali-Fazal et al. [15] reported that, at their institution, AIS was most commonly detected by laypersons and that this had increased since 1985 (i.e., after the UK concluded that screening should no longer be a national policy). At the time of their initial visit to an orthopaedic clinic, 70 % of the patients studied had a Cobb angle of more than 40°, as opposed to 28 % in 1985 [14].

The chosen recruitment period was unlikely to have been affected by changes in consultation volume or referral management, particularly as we did not have contact with the referring professionals. Selection bias should be limited since all referred patients were considered for inclusion in the study, the participation rate was high (89 %), non-participants did not differ from full participants on main outcome and on selected available variables. Our participants are believed to be representative of the children and adolescents consulting in paediatric orthopaedics in Quebec since the participating centres reach 70 % of this target population and that we have no reason to believe that the natural history of scoliosis or the referral patterns differ significantly in the rest of the province. Finally, we believe the results are generalizable to contexts where similar (universal) healthcare systems exist. In contexts where accessibility is a significant challenge, the role of laypersons could be even more important and could represent the primary focus for intervention.