Italian validation of INQoL, a quality of life questionnaire for adults with muscle diseases.
OBJECTIVE
A quality of life (QoL) questionnaire for neuromuscular diseases was recently constructed and validated in the United Kingdom in a sample of adult patients with a variety of muscle disorders. Preliminary results suggested it could be a more relevant and practical measure of QoL in muscle diseases than generic health measures of QoL. The purpose of our work was: (i) To validate INQoL in Italy on a larger sample of adult patients with muscle diseases (ii) to compare INQoL to SF-36.


METHODS
We have translated into Italian and applied language adaptations to the original UK INQoL version. We studied 1092 patients with different muscle disorders and performed (i) test-retest reliability (n = 80); (ii) psychometric (n = 345), known-group (n = 1092), external criterion (n = 70), and concurrent validity with SF-36 (n = 183).


RESULTS
We have translated and formally validated the Italian version of INQoL confirming and extending results obtained in the United Kingdom. In addition to good results in terms of reliability, known-group and criterion validity, a comparison with the SF-36 scales showed a stronger association between INQoL total index and SF-36 physical (r = -0.72) than mental (r = -0.38) summary health indexes. When considering comparable domains of INQoL and SF-36 with respect to an objective measure of muscle strength assessment (MMRC), regression analysis showed a stronger correlation using INQoL rather than SF-36 scores.


CONCLUSIONS
INQoL is recommended to assess QoL in muscle diseases because of its ability to capture physical limitations that are specifically relevant to the muscle condition.
Sansone
V A
VA
Department Neurology, University of Milan, IRCCS Policlinico San Donato.
Panzeri
M
M
Department Neurology, University of Milan, IRCCS Policlinico San Donato.
Montanari
M
M
Mario Negri Institute, Laboratory for Translational and Outcome Research, Department Oncology, Milan, Italy.
Apolone
G
G
Mario Negri Institute, Laboratory for Translational and Outcome Research, Department Oncology, Milan, Italy.
Gandossini
S
S
Department Neurology, University of Milan, IRCCS Policlinico San Donato.
Rose
M R
MR
Department Neurology, Kings College, University of London, London, UK.
Politano
L
L
Department of Cardiomyology and Clinical Genetic, University of Naples, Naples.
Solimene
C
C
Department of Cardiomyology and Clinical Genetic, University of Naples, Naples.
Siciliano
G
G
Department of Neurosciences, University of Pisa, Pisa.
Volpi
L
L
Department of Neurosciences, University of Pisa, Pisa.
Angelini
C
C
Department of Neurosciences, University of Padua, Padua.
Palmieri
A
A
Department of Neurosciences, University of Padua, Padua.
Toscano
A
A
Neurological and Neurosurgery Institute, University of Messina, Messina.
Musumeci
O
O
Neurological and Neurosurgery Institute, University of Messina, Messina.
Mongini
T
T
Department of Neurosciences, University of Turin, Turin.
Vercelli
L
L
Department of Neurosciences, University of Turin, Turin.
Massa
R
R
Department of Neurosciences, University of Tor Vergata and Fond IRCCS S Lucia, Rome.
Panico
M B
MB
Department of Neurosciences, University of Tor Vergata and Fond IRCCS S Lucia, Rome.
Grandi
M
M
Respiratory Physiopathology, Costa Masnaga, Como, Italy.
Meola
G
G
Department Neurology, University of Milan, IRCCS Policlinico San Donato.
D000328:Adult; D000367:Age Factors; D005260:Female; D006304:Health Status; D006306:Health Surveys / Q000379:methods / Q000592:standards*; D006801:Humans; D007558:Italy / Q000453:epidemiology; D008297:Male; D001523:Mental Disorders / Q000453:epidemiology / Q000523:psychology; D008875:Middle Aged; D018908:Muscle Weakness / Q000175:diagnosis* / Q000453:epidemiology / Q000523:psychology*; D009135:Muscular Diseases / Q000453:epidemiology / Q000523:psychology*; D011237:Predictive Value of Tests; D011788:Quality of Life / Q000523:psychology*; D011795:Surveys and Questionnaires / Q000592:standards*