Total Patient Delay: A comparison of patient and clinician/health system delays in the diagnosis of progressive supranuclear palsy and corticobasal syndrome

Background
Early diagnosis in progressive supranuclear palsy (PSP) and corticobasal syndrome (CBS) is important for clinical care and key to developing successful disease-modifying agents. The patient-dependent phases of decision-making made before contact with a healthcare professional have been inadequately studied.

Objectives
To evaluate the patient-dependent phases of decision-making from symptom onset, comparing this to clinician and/or health system delays within the overall diagnostic pathway.

Methods
Using the Anderson General Model of Total Patient Delay and a mixed-methods approach in participants with PSP/CBS and their caregivers recruited to the Scottish PSP and CBS cohort, we quantified and evaluated the determinants of “appraisal”, “illness,” and “behavioral” delay, comparing this to the clinician and/or health system delays (“treatment” delay) within the overall time from symptom onset to diagnosis.

Results
The time from index symptom onset to diagnosis was 3.26 (interquartile range [IQR] = 2.42, 4.75) years in PSP and 2.58 (IQR = 1.69, 4.08) years in CBS. Patient appraisal delay was 24 (IQR = 6, 60) weeks in PSP and 8 (IQR = 5, 24) weeks in CBS, illness delay 0 (IQR = −14, 0) weeks in PSP and 0 (IQR = −4, 0) weeks in CBS, with little perceived behavioral delay. Determinants of delay included the non-specificity of symptoms, normalization of symptoms within the context of age or normal physiological variability, and the extent of insight into new somatic symptoms.

Conclusions
Although patient appraisal delay contributes to overall diagnostic delay in PSP/CBS, the greater proportion of overall diagnostic delay arises after contact with a healthcare professional (treatment delay).