King’s staging provides convenient system for amyotrophic lateral sclerosis

The King’s College staging for amyotrophic lateral sclerosis (ALS) features a large degree of congruity, making it easy to remember and suitable for modeling the trajectory of limb- and bulbar-onset ALS in Singapore, suggests a new study.

“Knowledge of disease prognosis empowers clinicians to discuss disease prognosis with patients based on their symptomology,” the researchers said. “Moreover, knowledge of disease trajectory inferred from the staging model can be utilized by physicians to construct a patient-centred treatment plan that promptly anticipates and addresses the evolving needs of ALS patients.”

This retrospective cohort study sought to delineate the clinical trajectory of ALS in Singapore and test the degree of congruity of King’s staging among patients in the country.

The clinical milestones used for staging were identical to King’s staging: stage 1 corresponded to symptom onset; stage 2A to diagnosis; stage 2B to two central nervous system (CNS) regions; stage 3B to three CNS regions; stage 4A to requirement of supportive enteric feeding; and stage 4B to requirement of noninvasive ventilation, of which bulbar, diaphragmatic, upper and lower limb pyramidal involvements each constituted one CNS region.

The researchers then measured standardized timings from disease onset (0) to death (1) among 46 Singapore patients with ALS.

Of the patients, 22 were women (47.8 percent). Thirteen (28.3 percent; mean age, 63.77 years, 95 percent confidence interval [CI], 57.93–69.61) had bulbar-onset ALS, while the remaining 33 (71.7 percent; mean age, 60.42 years, 95 percent CI, 56.46–64.38) had limb-onset ALS. [Singapore Med J 2021;doi:10.11622/smedj.2021001]

Median survival was 27.4 months (95 percent CI, 18.2–36.6) among patients with bulbar-onset ALS and 32.06 months (95 percent CI, 24.07–40.05) among those with limb-onset ALS.

Results were chiefly in agreement with King’s staging. For patients with limb-onset ALS, results were as follows: diagnosis, 0.35; two CNS region involvement, 0.42; three CNS region involvement, 0.63; diaphragmatic involvement, 0.81; and bulbar involvement, 0.73. Outcomes for those with bulbar-onset ALS were as follows: diagnosis, 0.14; tow CNS region involvement, 0.28; three CNS region involvement, 0.42; diaphragmatic involvement, 0.62; and bulbar involvement, 0.67.

“From the retrospective review of the clinical records of 46 patients with ALS in our study, we were able to delineate the clinical trajectory of ALS among Singapore patients and establish similarity between the progression of our milestones and that of King’s staging,” the researchers said. [Brain 2012;135:847-852]

“The only exceptions were that in our study, patients with bulbar-onset ALS were diagnosed earlier in the disease trajectory, while those with limb-onset ALS needed non-invasive ventilation later in the disease trajectory,” they noted.

Similarities between the milestones assessed by this study and that by King’s College have the following implications: first, various ALS stages could be easily remembered; second, the staging system provides clinicians with knowledge that can be used to plan interventions concerning the evolving symptoms and needs of ALS patients; third, referencing the staging system will allow the healthcare team to anticipate the needs of patients by defining the disease course.

“There is room for future nationwide, multicentre prospective studies that place greater focus on the survival of patients with ALS,” the researchers said.