Студопедия

Главная страница Случайная страница

Разделы сайта

АвтомобилиАстрономияБиологияГеографияДом и садДругие языкиДругоеИнформатикаИсторияКультураЛитератураЛогикаМатематикаМедицинаМеталлургияМеханикаОбразованиеОхрана трудаПедагогикаПолитикаПравоПсихологияРелигияРиторикаСоциологияСпортСтроительствоТехнологияТуризмФизикаФилософияФинансыХимияЧерчениеЭкологияЭкономикаЭлектроника






Discussion






We investigated the rate of radiographic progression in 94 patients with JIA, all of whom had polyarthritis with symmetric involvement of the wrists. The wrist joint is affected in ∼ 60% of JIA patients, being second only to the frequency of knee joint involvement (21), but this frequency is much higher if only the polyarticular forms of JIA are considered. The wrist, together with the hip, is the site most vulnerable to changes seen on radiographs in patients with JIA (22, 23). Furthermore, wrist disease has been associated with a more severe course of arthritis (24, 25), a poorer functional outcome (23), and a lower likelihood of a short-term therapeutic response (26). Notably, all but 5 patients had resistant disease, which was judged severe enough to warrant treatment with a second-line drug, typically, methotrexate. Thus, our patient cohort had most of the clinical features that identify the subset of JIA patients who are at risk of joint destruction and poor functional outcome (2).

The potential for deterioration during the disease process was further demonstrated by the fact that patients experienced, on average, a significant increase in radiographic damage over time. Radiographic progression, however, was more pronounced during the first year of observation than during the remaining period of followup. These findings support the view that in polyarticular JIA, radiographic damage is common and occurs early (2). Similarly, radiographic damage has been shown to develop early in the disease course in adults with rheumatoid arthritis (27–29), with the rate of progression decreasing during the subsequent years of disease (30, 31). It must be noted that since the Poznanski score is a measure of cartilage loss, its sensitivity can be reduced in cases of advanced cartilage thinning. We therefore cannot exclude the possibility that a ceiling effect could partly account for the observed reduction in radiographic progression after the first year of followup. However, an increase in the number of patients who improved over the years of study could also have played a role. It is well known that the regenerative capacity of articular cartilage is better in growing children than in adults (10). Furthermore, the majority of the study patients had received second-line therapy with methotrexate, which has been shown to have a “disease-modifying” effect in JIA (10, 11).

Several studies have examined factors that may affect radiographic outcome in JIA. However, the results of these studies are not easily compared with ours because the development of radiographic damage has rarely been assessed by serial radiographs and by a standardized scoring system in JIA. Reported correlates of radiographic joint destruction include early onset, early radiographic abnormalities, presence of IgM rheumatoid factor, presence of HLA–B27, symmetric or more severe arthritis, the duration of active disease, and in patients with systemic disease, persistent systemic symptoms and thrombocytosis at and beyond 6 months (2, 21, 32–34). We found that the radiographic progression in the first year of followup was independently related to both the yearly radiographic progression during the entire study period and the amount of radiographic damage at the final visit. The degree of damage at baseline was also associated with an increase in total damage. Since patients had different disease durations at study entry, however, it was likely that the amount of radiographic damage at baseline would be different. Whether the presence of radiographic damage at baseline reflected a rapid deterioration or a relatively late diagnosis cannot be determined from our data. Nevertheless, it can be concluded that either the presence of early damage or the early development of damage predicts further deterioration. Because there may often be a significant lag time between clinical manifestations and the occurrence of radiographic changes and because cartilage loss may develop earlier than expected in JIA patients, the initial radiographic assessment for the purposes of clinical predictions should be done early in the disease course (i.e., within 6–12 months after initial presentation of symptoms).

Our female patients appeared to be protected against long-term radiographic progression as compared with our male patients. An association between male sex and a worse radiographic outcome has previously been reported (11, 35). However, other studies have found that female sex is the strongest risk factor for long-term disability (23, 33, 36), or they have failed to identify sex as one of the significant predictors of any outcome (20). In our study, the relatively greater likelihood of radiographic progression among the male patients might be partly explained by the fact that there were more male patients in the systemic disease subtype (43%) than in the other disease subtypes (28% in all other groups). Indeed, the systemic subtype (as compared with the other subtypes) was found to be strongly correlated with both long-term radiographic progression and joint damage by univariate analyses, although it did not enter any of the logistic regression models. Among JIA patient cohorts followed up for median intervals of 6–9 years, the frequency of destructive changes has been reported to be higher in the systemic subtype than in the other subtypes, except for the rheumatoid factor–positive polyarticular subtype (23). This latter subtype accounted for only 3 patients in our series.

In the few studies that have examined the relationship between radiographic damage and disability in JIA, significant correlations between joint changes and greater levels of disability, as assessed by the Steinbrocker criteria or the C-HAQ, have been reported (for review, see ref. 23). We found that early progression of damage predicted long-term disability, as assessed by the C-HAQ. This observation was strengthened by the strong correlation between the yearly radiographic progression and both the C-HAQ score and the number of joints with limited range of motion at the final visit. These results indicate that there is a close relationship between structural damage and functional impairment over the course of JIA and suggest that the early progression of damage may help to identify at an early stage those patients who are at greater risk of poor functional outcome.

Among the measures of disease activity at the final visit, neither the subjective assessments made by the physicians or the children's parents nor the ESR or CRP values were related to the yearly radiographic progression. However, the yearly radiographic progression was strongly related to the number of joints with active disease, which suggests that greater articular damage was associated with continued joint inflammation. Studies in adult patients have shown that cumulative joint inflammation increases the risk of progression of joint damage (37). Thus, therapy aimed at suppressing joint inflammation early in the course of JIA may prevent the progression of joint damage.

Our study indicates that the Poznanski method is a reliable and sensitive instrument for assessing the progression of radiographic damage in patients with JIA. It has the advantages of being simple, quick, and reproducible, and it requires little specific training. Thus, it can be easily applied not only in therapeutic trials, but also in clinical settings. Availability of standards for normal carpal length is another advantage in studies of growing children. Furthermore, since the RM width is not dependent on the degree of ossification of the carpal bones, its measurement helps to overcome the problem of advanced skeletal maturation, which occurs frequently in JIA (38).

The Poznanski method has some disadvantages, however; it can be used only in patients with wrist involvement, it is unreliable in cases of advanced carpometacarpal erosions, making it difficult to define the bone ends, and it cannot be used once there is radiographic closure of the growth plates of the second metacarpal bone. Concerning this latter point, Zerin et al (39) reported that in none of their JIA patients with apparent radiographic closure of the growth plates of the second metacarpal bones did this occur prematurely in comparison with the published norms. Another potential problem with the Poznanski method is whether isolated measurement of the wrist represents a good surrogate measure of the severity of erosive joint disease in other joints throughout the body. Using a different scoring system, van Rossum et al (34) found that abnormalities seen on radiographs of the hand did not correlate well with radiographic abnormalities of other joint groups.

Because JIA patients are often small for their age and their bones are correspondingly small, age-related standards are not reliable. In the Poznanski method, therefore, the carpal width (RM) is compared with the length of an adjacent bone (M2) rather than with age. Indeed, it is believed that the RM width is more closely correlated with stature than with age, and stature correlates well with M2 (10). This approach allows a measure of joint size that is relatively independent of the size of the child. Zerin et al (39), however, reported that patients with polyarticular JIA may develop early retardation of the growth of the M2 bone that is disproportionately more severe, as well as more rapid in its progression over time, than the impairment of the patient's height. They also found that this disproportion increases with increasing duration of disease. We did not confirm these findings because in our patients, the Z scores for the M2 length and the height were strongly correlated throughout the disease course, indicating that there was no disproportionate retardation of growth of the M2 bone compared with the patient's height. Our finding of a relationship between growth retardation of the M2 bone and disease duration and radiographic progression is not surprising because it is well known that patients with severe, longstanding polyarticular JIA, particularly of systemic onset, most often experience impaired growth in terms of overall height (and, therefore, in terms of M2 length) (1).

In summary, our patients with polyarticular-course JIA experienced, on average, a significant radiographic progression over time, as measured by the Poznanski score. Radiographic progression was more pronounced during the first year of observation. Changes in the early Poznanski score were consistently predictive of yearly radiographic progression, long-term joint damage, and physical disability. These findings indicate that the Poznanski score is a meaningful outcome measure in JIA and that its measurement early in the disease course can help to identify those patients who are at greater risk of joint destruction and poor functional outcome.

 






© 2023 :: MyLektsii.ru :: Мои Лекции
Все материалы представленные на сайте исключительно с целью ознакомления читателями и не преследуют коммерческих целей или нарушение авторских прав.
Копирование текстов разрешено только с указанием индексируемой ссылки на источник.