The validity, reliability, responsiveness and minimal clinically important difference of the de Morton mobility index in rehabilitation

Abstract

Purpose: Determine the clinimetric properties of the de Morton Mobility Index (DEMMI) in an adult inpatient rehabilitation population.

Method: Prospective open cohort case series. DEMMI and functional independence measure assessed within three days of admission and discharge and seven-point Likert assessment of global change in mobility during inpatient rehabilitation reported by the patient, physical therapist and rehabilitation physician.

Results: A total of 366 patients had assessments of the DEMMI completed on both admission into and discharge from rehabilitation. There was no floor or ceiling effect observed in the sample, but there was a mild (19%) ceiling effect at discharge in patients with a stroke. Evidence was obtained for the convergent, discriminant and known group validity of the DEMMI. The minimal clinically important difference was obtained using two methods. The DEMMI was highly responsive to change (Cohen’s d = 1.3).

Conclusions: The findings give support to the use of the DEMMI in rehabilitation patients and on the basis of previous studies, support the use of the DEMMI across the continuum of hospital settings.

Implications for rehabilitation

• This study provides evidence that the clinimetric properties of the de Morton Mobility Index (DEMMI) are sound.

• The findings give support to the use of the DEMMI in rehabilitation patients.

• Our findings, in conjunction with previous research, support the use of the DEMMI across the continuum of hospital settings.

Keywords:

• Mobility limitation
• outcome assessment (health care)
• psychometrics
• de Morton Mobility Index

Acknowledgements

The authors would like to thank Bianca Fedle (Epworth-Monash Rehabilitation Medicine Unit) for performing the data entry and assisting with the data quality checks.

The following physical therapists are thanked for their assistance with data collection: Chris Allen, Stephanie Allen, Jussyan Basilios, Charlotte Scroggie, Brooke Brimelow, Sarah Davies, Dianne DeVos, Veronica Elias, Sarah Elliot, Kantaro Ito, Faye Marshall, Jessie Mayo, Adam McKinstry, Sarah Milne, Praveen Mulinti, Dina Pogrebnoy, Priya Rangarajan, Hanna Sharma, David Snowdon, Lara Steele, Julius Ting, Krista Verstraelen, Jenny Wong and especially Alexander Caravelas.

Dr Hean See Tan is thanked for her assistance with the rehabilitation physician reporting of perceived improvement in mobility.

Disclosure statement

The authors report no conflicts of interest.