Parkinson Disease Diagnosis: MDS Criteria

Recent diagnostic criteria from the Movement Disorder Society (MDS) for Parkinson Disease (PD) accurately diagnose PD in 90% of clinically diagnosed cases, according to a study published online in Parkinsonism and Related Disorders.^1,2

The study is the first to test the MDS diagnostic criteria for PD in a large group of patients with clinically diagnosed PD.

“In our cohort, the MDS diagnostic criteria are at least 90% sensitive compared to the most commonly used preceding criteria,” wrote first author Naveed Malek, MD, of Ipswich Hospital NHS Trust (Ipswich, United Kingdom), and colleagues.

No biomarker or specific imaging test yet exists for PD, leaving the diagnosis heavily dependent on clinical evaluation, for which the accuracy is estimated at about 80%. To improve diagnosis, the MDS developed criteria that incorporate updated knowledge about PD and conditions that mimic it. The criteria retain the core definition of parkinsonism (bradykinesia, rigidity, and/or resting tremor) as well as red flags and absolute exclusion criteria that may help rule out the diagnosis. An advantage of the MDS criteria is that they emphasize clinical features inconsistent with the diagnosis of PD, such as vertical gaze palsy, absence of L-DOPA response, and pyramidal signs. Using the criteria, patients are categorized as non-PD, “clinically probable,” or “clinically established.”

The study included 2000 patients with PD diagnosed within the past 3.5 years using United Kingdom (UK) Brain Bank criteria. Included individuals were part of the Tracking Parkinson’s study, a large multicenter prospective study in the UK. Because the MDS criteria were published after recruitment for the study ended, the criteria were applied retrospectively to evaluate their accuracy in diagnosing PD. Included patients had a mean age of 64.4 years, disease duration of 1.3 years, were 64.9% male.

Key results:

• 91.7% (n=1835) of cases met MDS criteria for PD

♦ 63.1% (n=1261) had clinically established PD

♦ 28.7% (n=574) had clinically probable PD

♦ 8.3% (n=165) did not fulfill MDS criteria for PD

• Non-PD cases fared worse on a number of variables:

♦ Worse cognition: significantly more dementia with non-PD (21.7%) vs probable PD (15.5%, P=0.013), and established PD (13%, P=0.02)

♦ Worse motor symptoms: Higher mean UPDRS3 score with non-PD (25.1) vs probable PD (22.3, P=0.016) and established PD (22.9, P=0.066)

♦ L-DOPA dose: significantly higher with non-PD (341 mg) vs probable PD (250 mg, P<0.001) and established PD (308 mg, P=0.025)

• After 2.5 years of follow-up:

♦ 89.5% of established PD at baseline remained established or became probable PD

♦ 86.9% of probable PD remained probable or became established

♦ 5.5% of non-PD became probable PD

The authors pointed out that about 1 in 10 cases of clinically established PD became clinically probable over 2.5 years, and that around 1 in 4 cases of clinically probable cases became clinically established. However, only 3% of cases categorized as non-PD may actually have had PD.

“[T]he MDS criteria for PD are useful for corroborating the diagnosis of PD, amongst cases fulfilling the core definition of parkinsonism and with a clinical PD diagnosis, and helpful in categorizing levels of diagnostic certainty. Cases not fulfilling MDS diagnostic criteria for PD have more severe parkinsonism, in particular relating to postural instability, gait problems, and cognitive impairment,” they concluded.

Take-home Points

• A retrospective study found the Movement Disorder Society criteria for diagnosing PD were accurate in over 90% of clinically diagnosed cases.

• Patients who did not meet MDS criteria for PD had more severe parkinsonism, worse cognition, and higher doses of L-DOPA.

• Over 2.5 years of follow-up, 1 in 10 cases of clinically established PD became clinically probable, 1 in 4 cases of clinically probable cases became clinically established, and only 3% of cases of non-PD may actually have had PD.

One or more authors reports advisory board membership, honoraria, grants, and/or consulting for one or more of the following:  UCB, Teva Lundbeck, Britannia, GSK, Boehringer, GE Healthcare, Lily Pharma, Medtronic, Parkinson's UK, NIHR, Cure Parkinson's Trust, Evelyn Trust, Rosetrees Trust, MRC, EU, Oxford Biomedica, LCT, Lilley, Wiley, Springer, NIHR, Wellcome Trust, GlaxoSmithKline Ltd, Parkinson's UK, Michael J Fox Foundation, Eisai, MRC/Wellcome, Medical Research Council UK, Ipsen Fund, Motor Neuron Disease Association, Welsh Assembly Government, PSP Association, CBD Solutions, Drake Foundation, Teva, AbbVie, Civitas, and/or Acorda.

References:

1. Malek N, et al for the PRoBaND clinical consortium. Utility of the new Movement Disorder Society clinical diagnostic criteria for Parkinson's disease applied retrospectively in a large cohort study of recent onset cases. Parkinsonism Relat Disord. 2017 Apr 12.

2. Postuma RB, et al. MDS clinical diagnostic criteria for Parkinson's disease. Mov Disord. 2015;30(12):1591e1601.