Background
Adherence is defined as the degree to which a patient acts in accordance with the prescription of a health care provider. As attested by the results of clinical research [
1], it has unquestionable implications on the effect of a therapy. The harder the treatment, the higher the risk of non-compliant patients. Brace wear for scoliosis is a very hard and complex therapy; indeed, wearing plastic for a long time and during one of the most critical phases of life, namely adolescence [
2,
3], can be a real challenge.
In everyday practice, adherence is often assessed through self-completion questionnaires, or is self-reported, despite the recognized low reliability thereof [
4,
5]. Therefore, objective compliance monitors were introduced, at first only for research purposes [
4,
6‐
11]. Several studies demonstrated the reliability of temperature sensors, and, as a consequence, investigation into the effects of adherence on results started [
6‐
11]. A prospective study on 495 scoliosis patients treated with a Boston brace concluded that the risk of curve progression and the need for surgery decreases in patients with good compliance [
5]. In the same study, brace efficacy was confirmed by a multicenter RCT [
12] and compliance was assessed through the use of objective monitors. A relation between dosage and results was found, thus confirming previous research: the more the brace is worn, the better the results [
9‐
12]. Most of the results obtained with the compliance monitor showed a poor adherence to bracing [
4,
10,
11,
13], as might be expected, considering the huge engagement required for such a hard therapy. Conversely, one paper subverted previous findings and demonstrated that it is possible to obtain higher adherence, even with full-time prescription. In addition, this device proved very helpful to everyday clinical activity, offering valuable help in therapeutic choices without undermining the relationship with patients and family [
14]. The standardized everyday clinical usage of this temperature sensor, called Thermobrace, improves the quality of treatment through the optimization of the dosage. In fact, the use of Thermobrace in all subjects with a brace prescription has been shown to also contribute to the cognitive behavioral approach [
15], which is able to enhance compliance. In a recently published survey, scoliosis patients and their families showed a very positive attitude towards these electronic devices [
16].
Thinking about the biomechanics of the spine, a good consistency in terms of the duration of pauses, namely the same number of hours each day, enhances the spine’s support ability, thus improving results. Conversely, a higher variability in break lengths would undermine the support of the spine, and favors the mobilization of the spine. Actually, when the brace is on, the spine is straightened and corrected [
17‐
19]; out of the brace, the spine collapses [
20,
21] in a very short time. Based on this theory, brace prescriptions used to recommend that the brace be worn at all times, and always for the same number of hours, discouraged patients from wearing the brace less than 1 day and wearing it for an increased duration the next. Therefore, we can define the treatment as the summation of the hours of brace wear per day (with a regular daily pattern). The standard use of the TB since 2010 has demonstrated that, among patients with the same mean compliance, there are some who produced very homogeneous brace wear data and some who had days of higher break duration and days with no breaks. This can result in skewed data, with a high variability. Therefore, beyond the classification of patients based on the rate of hours per day of brace wear in relation to the prescription, a further categorization can be applied to distinguish the consistency of brace wear, thus referring to a “daily pattern compliance.”
The main hypothesis we aimed to test in this study was the following: can the hours per day of brace wear, as very close to that specified in the prescription, together with the consistency of brace wear, which means a very regular pattern of compliance, positively affect short-term results?
Results
Out of the 168 patients (105 females), 104 were classified according to the daily pattern compliance as having consistent brace wear, and 64 as having inconsistent brace wear. We did not find statistical differences in all primary parameters between consistent and inconsistent brace wearers, except for the gender distribution, which showed a higher rate of males in the fickle brace wear group (Table
1). Table
2 shows the results for the two groups of different daily pattern compliance, according to brace wear adherence (defined as high, medium, or low).
Table 1
Primary parameters in the two groups considered
Mean age (SD) | 13.7 (1.8) | 12.9 (1.9) | NS |
Mean Cobb degrees (SD) | 41.1 (11.8) | 41.7 (11.2) | NS |
Males | 50 (78.1%) | 13 (12.5%) | < 0.001 |
Females | 14 (21.9%) | 91 (87.5%) | < 0.001 |
Table 2
Results of the two groups of different daily pattern compliance, according to the brace wear adherence (defined as high, medium, or low)
Consistent daily pattern n (%) 104 (61.9%) | 55 (52.8%) | 38 (36.6%) | 11 (10.6%) |
Hours/day compliance* | Hours/day compliance | Hours/day compliance |
High | Medium | Low | High | Medium | Low | High | Medium | Low |
29 (54.1%) | 26 (47.3%) | 0 (0%) | 13 (35.2%) | 25 (65.8%) | 0 (0%) | 1 (9.6%) | 10 (90.4%) | 0 (0%) |
Inconsistent daily pattern n (%) 64 (38.1%) | 24 (39.1%) | 36 (54.7%) | 4 (6.3%) |
Compliance | Compliance | Compliance |
High | Medium | Low | High | Medium | Low | High | Medium | Low |
7 (10.9%) | 12 (18.8%) | 5 (9.4%) | 7 (10.9%) | 16 (23.4%) | 13 (20.3%) | 0 (0%) | 3 (4.7%) | 1 (1.6%) |
Subjects with an adherence of below 94% (classified as low and medium compliers), and with inconsistent daily pattern compliance, are more likely to progress than those with a consistent daily pattern compliance (OR 0.19 CI 95% 0.096–0.37 chi-square 23.12 p = 0.0000).
The results concerning the measures of association showed that consistent daily pattern compliance is associated with a higher probability of improvement in curve magnitude after the first few months of treatment (OR 1.96 CI 95% 1.22–3.14 chi-square 7.78 p = 0.0053). Consequently, inconsistent daily pattern compliance is more likely to progress (OR 0.14 CI 95% 0.30–0.75 chi-square 10.13 p = 0.0015).
Adherence was very high in the consistent brace wear group. 81.70% of patients were high compliers, which means over 95% of the prescription. In the inconsistent daily pattern compliance group, the proportion of subjects with high adherence was 21.80% (p < 0.0001); among these, 50% improved and 50% remained stable.
Inconsistent daily pattern compliers tended to be categorized as medium or low compliant. Consistent daily pattern compliers were generally adherent to the prescription, regardless of the number of hours prescribed. Inconsistent daily pattern brace wearers were characterized by a negative correlation between the hours of prescription and compliance. Males were more likely to be inconsistent compliers than females. Indeed, males were more frequent in the inconsistent daily pattern compliance group (78.13% versus 12.50%; p < 0.05). The comparison of adherence according to curve magnitude demonstrated that the severity of the curve did not affect the adherence level or quality. Consistency in brace wear showed itself to be linked to a higher brace wear compliance, which is of relevance when determining short-term results together with the amount of compliance.
Adjusted for the brace wear adherence and the daily pattern compliance, the results of the logistic regression showed that the most influential factor for improvement was the Cobb degrees at start. Subjects with less than 35° at the beginning of the therapy were almost four times more likely to obtain a significant regression of curves (p = 0.001). Risser and gender had no significant influence on the results.
Discussion
Despite the hard engagement requested during brace therapy to ensure good results, our present and previous results confirm that it is possible to obtain a higher adherence to brace wear [
14] and that teamwork is fundamental to obtaining such adherence to treatment [
29]. When referring to brace therapy, dose and goals are strictly related. In scoliosis treatment, the main goal of brace therapy can change according to the curve magnitude and other key factors, all of which influence curve progression. Therefore, in some cases, an improvement is needed, while in other cases, a stabilization of the curves is enough [
23]. According to the scientific literature, the main outcome to be considered in the analysis of brace wear results is progression avoidance. The present research has deepened the issue of the best dosage and management of brace wear for AIS patients, by considering as main outcome not only the stabilization of curves, but also the possible improvement of curves [
27].
The standardized application of compliance monitors has already demonstrated various advantages [
14,
30]. Very recently, the relationship between adherence to the prescribed regimen and the results of the therapy was confirmed; but, more interestingly, Reinker and colleagues found that the awareness of being monitored and the possibility of discussing the objectively measured wearing time with the treating team improve compliance [
31].
The present study is the first in which the standardized application of the Thermobrace is used to analyze the short-term effects of brace therapy in respect not only to brace wear adherence, but also to daily pattern compliance. According to the present research, “consistent brace wear” plays a significant role in determining satisfactory results, compared to high adherence alone. Hence, high-quality brace wear is defined by both high adherence to the brace wear prescription and consistency in the daily pattern compliance. Very often, on any particular day, adolescents with scoliosis prefer to wear the brace for fewer hours than prescribed, and to recover time in the brace the day after. Parents often also prefer this kind of behavior. It involves 1 day of “maximum sacrifice” in order to gain some more hours of freedom. This behavior appears to favor brace adherence but, as demonstrated above, it can also affect results. In light of the present results, asking for slightly fewer hours of brace wear, but with the compromise of a high level of consistency, would be a better approach.
The Sforzesco brace has demonstrated its efficacy in curve improvement in previously published observational studies [
18,
24,
32,
33]. It is possible that brace efficacy confounds the present results. In fact, a more significant difference is seen in the comparison of improvement in respect to stabilization and worsening, so that the entire sample considered is unbalance in the improvement direction, and the rate of progress was very low. This is the reason why the measure of association produced OR values below one. All the statements below justify the choice of the main outcome of the actual research: the rate of improvement being associated with a high adherence to the brace wear prescription. The logistic regression analysis showed that the major confounder of the current results is the Cobb degrees at start; as expected, the milder curves are more likely to regress, while more severe curves tend to stabilize, rather than improve.
One of the hypotheses, which is relevant to the evidence presented, addresses the in-brace correction and the postural collapse already documented when out of the brace [
34]. At the start of breaks, the spine collapses quickly, thus losing its correction. Therefore, the longer the break, the higher the correction lost. At the end of this phase, the brace will, again, correct the spine. As the number of breaks increases, the mobilization of the spine can increase accordingly. This theory is the basis of the traditional recommendation that patients wear the brace regularly every day, respect their prescription very closely, and engage in the same number of hours of brace wear. Prior research in the field of postural and clinical changes at brace weaning [
20,
21] have shown that postural collapse is correlated to the length of brace weaning and to the flexibility of the spine.
One of the main limitations of the present study was the inclusion of AIS patients, regardless of curve magnitude, and the inclusion of very severe curves, together with milder scoliosis. A heterogeneity of data can produce biased results, and caution is needed in the interpretation of results thereof. During study planning, we decided to avoid any curve magnitude selection criteria, to guarantee a larger sample for the purpose of focusing on the main concerns: the effect of brace wear adherence combined with daily pattern compliance on short-term results. This choice was supported by previous findings in which brace wear was not influenced by curve magnitude nor curve type [
14,
35]. In addition, we strongly agreed that this behavior would have enhanced the generalizability of the results. Curve type was not considered among the influencing variables, because it showed an unbalanced distribution in the sample. The lateral view of the spine was not available for all the included subjects; therefore, global sagittal balance parameters were not considered, together with curve magnitude.
Conclusion
In clinical everyday activity, patients must be encouraged to be consistent and to follow their prescription for brace wear closely, because this attitude is clearly associated with a higher probability of improvement. Even with less adherent brace wear, consistency can be rewarded with better short-term results. During brace treatment, all the members of the team must endorse consistent and rigorous brace wear, as it has been clearly demonstrated that this attitude will produce better results.
The actual findings offer some contribution to clinical decision-making. Further analysis using long-term monitoring will consider all the possible effects associated with adherence to the treatment and the final results. The usefulness of the everyday standardized application of the Thermobrace has been confirmed once again.