Research Proposal: Nursing Interventions To Decrease Complications Of Diabetes
The dilemma of diabetes in chronic inflammatory demyelinating polyneuropathy
Vera Brila, Christopher M. Blanchetteb, Joshua M. Nooneb, M. Chris Runkenc, Deborah Gelinasc, and James W. Russelld,*
aDivision of Neurology, University of Toronto, 200 Elizabeth St, 5EC-309, TGH, Toronto, ON, M5G 2C4, Canada
bDepartment of Public Health Sciences, University of North Carolina at Charlotte, 9201 University City Blvd, Charlotte, NC 28223, USA
cDepartment of Medical Affairs, Grifols, 79 TW Alexander Dr. Bldg 4101 Research Commons, Research Triangle Park, NC 27709, USA
dDepartment of Neurology, University of Maryland School of Medicine, and VA Maryland Health Care System, 110 S Paca Street, 3S-129, Baltimore, MD, 21201, USA
Abstract
Purpose—We reviewed the literature on chronic inflammatory demyelinating polyneuropathy (CIDP) in diabetes mellitus (DM) and explored real-world data on the prevalence and treatment of
CIDP within DM. Methods: A literature search of Scopus was performed for the terms chronic inflammatory demyelinating polyradiculoneuropathy, chronic inflammatory demyelinating polyneuropathy, CIDP, and prevalence, incidence, epidemiology, or diabetes; peripheral neuropathy and prevalence or diabetes. We also searched through the reference lists of the resulting publications for additional findings that may have been missed. Additional publications
on guidelines for the diagnosis of CIDP and diabetic neuropathy were also included. A descriptive
analysis of the 2009–2013 PharMetrics Plus™ Database was performed to estimate the prevalence
and treatment of CIDP within the DM population.
Results—There is an increasing body of literature suggesting that the prevalence of CIDP tends to be higher in diabetic patients, especially in those of older age. Our real-world data seem to
support published findings from the literature. For the total cohort (N = 101,321,694), the percent
prevalence of CIDP (n = 8,173) was 0.008%; DM (n = 4,026,740) was 4%. The percent prevalence
of CIDP without DM (n = 5,986) was 0.006%; CIDP with DM (n = 2,187) was 9-fold higher at
0.054%. For patients >50 years old, there was a significantly higher percentage of CIDP with DM
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/). *Corresponding author at: Department of Neurology, University of Maryland School of Medicine, 110 S Paca Street, 3S-129, Baltimore, MD, 21201. Tel.: +1 410 328 3100; fax: +1 410 328 8981., Russell@som.umaryland.edu (J.W. Russell).
Conflict of Interest Disclosure: V.B. has received grant funding from Grifols, CSL Behring, and Alexion; has consulted for Grifols, CSL Behring, Alexion, and Bionevia; and has participated as a speaker on behalf of Grifols. D.G. and M.C.R. are employees of Grifols. C.M.B. and J.M.N. have received consulting fees from Grifols for this study. J.W.R. is supported in part by the Office of Research Development, Department of Veterans Affairs (Biomedical and Laboratory Research Service and Rehabilitation Research and Development, 101RX001030) and Baltimore GRECC. There are no other relevant conflicts of interest.
U.S. Department of Veterans Affairs Public Access Author manuscript J Diabetes Complications. Author manuscript; available in PMC 2017 July 26.
Published in final edited form as: J Diabetes Complications. 2016 ; 30(7): 1401–1407. doi:10.1016/j.jdiacomp.2016.05.007.
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http://creativecommons.org/licenses/by-nc-nd/4.0/
than CIDP without DM. Approximately 50% of CIDP patients were treated with IVIg, 23%–24%
with steroids, 1%–2% with PE, and 20%–23% received no treatment.
Conclusions—In addition to the growing evidence of higher prevalence of CIDP in DM, our findings reinforce the need for heightened awareness of the association of CIDP and DM.
Keywords
Chronic inflammatory demyelinating polyneuropathy; CIDP; Diabetes mellitus; Diabetic peripheral neuropathy; Prevalence; Diabetic peripheral neuropathy
Chronic inflammatory demyelinating polyneuropathy (CIDP) is a heterogeneous,
progressive or relapsing–remitting, immune-mediated disorder of the peripheral nervous
system that has an estimated prevalence of 1–8.9 per 100,000 (Chio, Cocito, Bottacchi, et
al., 2007; Hafsteinsdottir, Olafsson, & Stefansson, 2012; Laughlin, Dyck, Melton, et al.,
2009; Lunn, Manji, Choudhary, et al., 1999; McLeod, Pollard, Macaskill, et al., 1999;
Mygland & Monstad, 2001; Rajabally, Simpson, Beri, et al., 2009). The epidemiology of
CIDP varies depending on the diagnostic criteria used (Rajabally, Simpson, et al., 2009).
CIDP has typical and atypical phenotypic variants (Mathey, Park, Hughes, et al., 2015).
Only half of CIDP patients have typical CIDP, which exhibits symmetrical sensory and
motor symptoms. The remainder has atypical disease, which presents with predominantly
focal, sensory, motor, distal or asymmetrical symptoms. Despite increased efforts to identify
a biomarker, there is no definitive diagnostic marker for CIDP, and recognition of CIDP is
not straightforward in some cases due to its heterogeneous nature (Jann, Bramerio, Beretta,
et al., 2003; Latov, 2011; Sommer & Toyka, 2011).
A thorough literature search of Scopus—an abstract and citation database of peer-reviewed
literature—was performed for all publications, including but not limited to case reports,
reviews, clinical studies, meeting abstracts, book chapters, for the terms chronic inflammatory demyelinating polyradiculoneuropathy, chronic inflammatory demyelinating polyneuropathy, CIDP, and prevalence, incidence, epidemiology, or diabetes; peripheral neuropathy and prevalence or diabetes. We also searched through the reference lists of the resulting publications for additional findings that may have been missed. All publications
included were in the English language, and there was no limit on year of publication.
Additional publications on guidelines for the diagnosis of CIDP and diabetic neuropathy
were also included.
1. Diagnosis of CIDP
The diagnosis of CIDP is based on the recognition of clinical features, neurological
examination, and electrodiagnostic criteria. Electrodiagnostic studies include
electromyograms and nerve conduction studies (NCSs). Nerve conduction studies and
electrophysiological evidence of demyelination are required to confirm the diagnosis (AAN,
1991; EFNS/PNS, 2010; Krarup, 2003; Latov, 2014; Tesfaye, Boulton, Dyck, et al., 2010),
while laboratory testing, elevated protein levels in cerebrospinal fluid (CSF), and nerve
biopsy can help rule out other causes for neuropathy and support the diagnosis (EFNS/PNS,
2010; Koller, Kieseier, Jander, et al., 2005). As the disease progresses, electrophysiological
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evidence of axonal damage may become superimposed on the demyelinating CIDP features
(Hughes, Allen, Makowska, et al., 2006). Patients with CIDP typically present with
progressive weakness in both proximal and distal muscles, areflexia, sensory symptoms with
proximal weakness, and preferential loss of sensation for vibration or joint position (EFNS/
PNS, 2010). Clinical observations of muscle weakness and loss of sensation are
manifestations of nerve demyelination that result in conduction blocks and delays in
conduction speed.
The 2010 European Federation of Neurological Societies/Peripheral Nerve Society (EFNS/
PNS) guidelines are globally accepted for both clinical and research purposes (EFNS/PNS,
2010; French & Vallat, 2008; Koski, Baumgarten, Magder, et al., 2009; Rajabally, Fowle, &
Van den Bergh, 2015; Rajabally, Nicolas, Pieret, et al., 2009) due to their balance between
high sensitivity (73.2%) and specificity (90.8%) for CIDP (Breiner & Brannagan, 2014;
Rajabally, Simpson, et al., 2009; Rajabally et al., 2015). In contrast, the American Academy
of Neurology (AAN) criteria (AAN, 1991) can have a sensitivity as low as 3.6% and a
specificity of 100% for CIDP. The EFNS/PNS guidelines define CIDP as “definite,”
“probable,” or “possible” based on specifics surrounding motor distal latency prolongation,
reduction of motor conduction velocity, prolongation or absence of F-waves, motor
conduction block, and distal compound muscle action potential (CMAP) duration (EFNS/
PNS, 2010). Testing of multiple limbs is more sensitive than testing of unilateral or lower
limbs in optimizing electrodiagnostic testing for CIDP, particularly in atypical CIDP (Chin,
Deng, Bril, et al., 2015; Rajabally, Jacob, & Hbahbih, 2005; Vo, Hanineva, Chin, et al.,
2015). Additional tests that may be needed to support a diagnosis of CIDP are elevated CSF
protein with a leukocyte count less than 10/mm3, magnetic resonance imaging (MRI) of the
lumbosacral or cervical nerve roots or the brachial or lumbosacral plexuses, nerve biopsy,
and clinical improvement after immunomodulatory treatment (Abe, Terashima, Hoshino, et
al., 2015; EFNS/PNS, 2010; Midroni, de Tilly, Gray, et al., 1999). Newer techniques for
detecting proximal demyelination as well as treatment response include ultrasonography (Di
Pasquale, Morino, Loreti, et al., 2015; Guidon, 2015; Jang, Cho, Yang, et al., 2014;
Kerasnoudis, Pitarokoili, Behrendt, et al., 2014; Kerasnoudis, Pitarokoili, Behrendt, et al.,
2015; Kerasnoudis, Pitarokoili, Gold, et al., 2015), magnetic stimulation of the cauda equine
(Maccabee, Eberle, Stein, et al., 2011), somatosensory evoked potentials (Devic, Petiot, &
Mauguiere, 2015), MRI gadolinium enhancement of the spinal nerve roots (Midroni et al.,
1999), and magnetic resonance neurography with 3-dimensional reconstruction to determine
patterns of nerve hypertrophy and to differentiate the pathophysiology of CIDP subtypes
(Shibuya, Sugiyama, Ito, et al., 2015).
2. Diabetes mellitus and diabetic neuropathies
According to the Centers for Disease Control and Prevention, DM affects about 9.3% of the
general population in the United States in contrast to 25.9% in persons 65 years or older
(CDC, 2014). Type 2 DM (T2DM) results in insulin resistance and accounts for >90% of
cases (Handelsman, Mechanick, Blonde, et al., 2011; Russell & Zilliox, 2014). The
prevalence of T2DM increases with age, elevated body mass index, and family history
(Handelsman et al., 2011). Due to the gradual onset of T2DM, early symptoms often go
unrecognized (Russell & Zilliox, 2014). Some investigators report CIDP to be more frequent
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in patients with T2DM (Dunnigan, Ebadi, Breiner, et al., 2013), while others report equal
occurrence of CIDP in type 1 DM and T2DM (Sharma, Cross, Ayyar, et al., 2002). While it
is estimated that 50% of patients with DM have some form of neuropathy, more than 80% of
these cases are diabetic peripheral neuropathy (DPN)—a length-dependent, sensory more
than motor, axonal neuropathy (Chin & Rubin, 2010). Early signs of DPN manifest through
distal loss of sensation in the feet and/or loss of deep tendon reflexes at the ankles. The risk
of developing DPN increases with the duration of DM and glycemic control, and DPN may
precede the formal diagnosis of DM by years (Chin & Rubin, 2010; Handelsman et al.,
2011; Russell & Zilliox, 2014).
3. Controversy: the association of CIDP and DM
In the 1975 seminal paper on CIDP (Dyck, Lais, Ohta, et al., 1975), Dr Peter J. Dyck stated,
“Patients with diabetes mellitus […] who had a neuropathy whose clinical,
neurophysiologic, and pathologic features were indistinguishable from the neuropathy
studied here, have not been included under this designation [of CIDP] even though it may be
shown eventually that pathogenetic mechanisms may be similar or alike.”
Forty years later, the association between CIDP and DM is still being debated. Diagnosing
CIDP in a patient with DM is more challenging, as superimposed axonal damage can
obscure electrophysiology findings of CIDP, and DPN can cause elevated CSF protein
(Gorson, Ropper, Adelman, et al., 2000). One study has reported that the occurrence of
CIDP is 11-fold higher in diabetic than nondiabetic patients; however, this was a smaller
nonpopulation based study (Sharma, Cross, Farronay, et al., 2002). Another study estimated
that CIDP occurs in 9% of patients with DM (Lozeron, Nahum, Lacroix, et al., 2002), while
others have reported that there is no association between CIDP and DM (Dyck, Engelstad,
Norell, et al., 2010; Laughlin et al., 2009). One publication stated that an overemphasis on
electrophysiological criteria may cause confusion in the perceived association between
CIDP and DM (Laughlin et al., 2009). However, that study was retrospective, had a small
CIDP population (only 19 patients met the Mayo Clinic clinical and electrophysiological
criteria for CIDP), was from a relatively limited patient demographic, and had only 1 patient
with both CIDP and DM. Moreover, full electrophysiological characteristics of subjects
were not reported. A subsequent report by the same authors investigated whether painless
diabetic motor neuropathy might represent CIDP (Garces-Sanchez, Laughlin, Dyck, et al.,
2011). Based on clinical presentation, electrophysiology, and a strong emphasis on sural
nerve biopsy, the authors concluded that painless diabetic motor neuropathy was a painless
form of diabetic lumbosacral radiculoplexus neuropathy, not CIDP.
Patients with both CIDP and DM tend to have extensive axonal loss with more severe
neuropathy yet may respond to treatment (Dunnigan, Ebadi, Breiner, et al., 2014; Gorson et
al., 2000). A small study comparing 14 patients with CIDP and DM to 60 patients with
CIDP alone, found that CIDP patients with DM were older (67 years vs. 49 years,
respectively) and had similar response rates to corticosteroids, intravenous immunoglobulin
(IVIg), plasma exchange (PE), and cyclophosphamide (Gorson et al., 2000). Patients with
CIDP and DM exhibited more severe axonal loss, likely the result of underlying diabetic
axonal polyneuropathy (Dunnigan et al., 2013). In contrast to patients with DPN (n = 56),
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diabetic patients with CIDP (n = 67) had more extensive slowing of motor nerve conduction
velocity (32.4 ± 6.4 m/s vs. 35.2 ± 3.4 m/s, P = 0.006). Diabetic patients with CIDP also tended to be older (65.1 ± 13.7 years vs. 55 ± 16 years, P = 0.0003), have shorter duration of diabetes (16.5 ± 13.5 years vs. 24.0 ± 15.6 years, P = 0.005), have more severe neuropathy (ie, higher Toronto Clinical Neuropathy Score, higher vibration perception threshold, and
more weakness), and have better glycemic control compared with diabetic patients who did
not have CIDP but had slowed conduction velocities (HbA1c 7.7 ± 2.0% vs. 9.6 ± 2.4%, P = 0.003).
EFNS criteria are less predictive of treatment response in CIDP patients with DM (Abraham,
Breiner, Katzberg, et al., 2015). CIDP patients with DM were more likely to respond to
treatment if they fulfilled 2 EFNS/PNS electrophysiological criteria whereas CIDP patients
without diabetes were likely to respond with only 1 criterion met (Table 1). In diabetics,
fulfilling more diagnostic criteria for CIDP (more evidence of demyelinating neuropathy on
NCSs) was associated with higher response rates to treatment (Cocito, Chio, Tavella, et al.,
2006). The recent retrospective study (Dunnigan et al., 2014) also demonstrated that patients
with CIDP and DM were less likely to be treated even though they had similar response
rates to treatment as CIDP patients without DM and higher rates of proximal weakness and
ataxia (Table 2).
4. Real-world data analysis of health insurance administrative claims
4.1. Methods
4.1.1. Database description—Controversies on the overlap of CIDP within DM led us to investigate the prevalence of CIDP and DM in a “real-world” health insurance
administrative claims database—the 2009–2013 Phar-Metrics Plus™Database (Watertown,
MA, USA). Secondary objectives were to determine any impact of age on the diagnosis of
CIDP patients both without and with DM and to highlight any differences in treatment
patterns. This database represents a pooling of adjudicated medical and pharmacy claims for
over 100 million patient lives from more than 90 different health plans across the United
States. The database includes inpatient and outpatient diagnoses in International
Classification of Diseases-9th Revision-Clinical Modification (ICD-9-CM) format;
procedures in Current Procedural Terminology-4th Edition and the Healthcare Common
Procedure Coding System; and prescription records (Blanchette, Roberts, Petersen, et al.,
2011). It also includes demographic variables, product and insurance type, provider
specialty, and dates inclusive of plan enrollment. This private database includes a limited
number of patients enrolled in Medicaid or Medicare and, therefore, underrepresents the
patient population older than 65 years. A typical limitation of any claims database analysis is
that clinical data are unavailable for the diagnostic criteria by which the diagnoses of CIDP
and DM were made. To ensure the robustness of this dataset, we applied stringent inclusion
criteria. Patients were confirmed with DM if there were ≥2 claims based on ICD-9-CM code
250. For a CIDP confirmation, patients were required to have ≥2 CIDP claims (ICD-9-CM
code 357.81) reported at least 90 days apart. Incident cases were defined as being free of a
CIDP diagnosis during the 12-month baseline period before their index date.
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4.1.2. Statistical analysis—Descriptive statistics were used to assess differences in the population. Chi-square tests were used to assess differences in age distributions between
CIDP patients without and with DM. Statistical significance was set at an alpha level of
0.05. This study was exempt from any institutional review board review because the patient
information within the database was de-identified.
4.2. Results of database analysis
In this retrospective database study (N = 101,321,694), the prevalence of patients with CIDP
(n = 8,173) was 8 per 100,000 persons (0.008%), which was similar to a previously reported
prevalence value of 8.9 per 100,000 persons (Laughlin et al., 2009). Reflective of the
generally younger patient population in the database, the overall prevalence of patients with
DM (n = 4,026,740) was 3,974 per 100,000 persons (4.0%), which was lower than the 9.3%
reported in the general United States population (CDC, 2014). However, in the population
older than 55 years (n = 2,461,140), the percent prevalence of patients with DM was 11,567
per 100,000 persons (11.6%). The prevalence of CIDP among nondiabetic patients (n =
5,986) was 6 per 100,000 persons (0.006%). In contrast, the prevalence of CIDP in the
diabetic population (n = 2,187) was 9-fold higher at 54 per 100,000 persons (0.054%). In
this claims database study, clinical data are not available, and the accuracy of the diagnoses
for DM and CIDP cannot be confirmed; yet the relative risk of having both CIDP and DM at
9-fold higher than having CIDP alone is approaching the 11-fold increase previously
reported by Sharma et al., using the highly specific AAN criteria (Sharma, Cross, et al.,
2002).
To improve the stringency around the CIDP diagnosis in this epidemiological cohort, we
mandated that confirmed CIDP cases have distinct ICD-9-CM codes reported at least 90
days apart. A total of 2,048 patients had confirmed CIDP with ≥12 months pre- and post-
index periods and ICD-9-CM codes of at least 90 days apart. Within this confirmed CIDP
group, 1,411 (69%) patients had CIDP without DM, and 637 (31%) patients had CIDP with
DM. These data were similar to the 25.7% of patients who had clinically confirmed CIDP
with DM in another database study (Kalita, Misra, & Yadav, 2007). In our current study, the
median ± standard deviation (SD) age was 56.4 ± 14.5 years for CIDP without DM and 61.6
± 11.8 years for CIDP with DM. In patients aged 50 years or younger, CIDP without DM
was more common than CIDP with DM (P < 0.01) (Fig. 1), suggesting that misdiagnosis of CIDP was not likely in this dataset. No difference in prevalence rates was found in patients
aged 51 to 60 years in both groups (29.98% CIDP without DM vs. 31.08% CIDP with DM,
P = 0.61). In those aged 61 to 70 years, there was a trend for CIDP with DM to be more common than CIDP without DM, but statistical significance was not reached (33.28% CIDP
without DM vs. 29.34% CIDP with DM, P = 0.07). Despite the relatively smaller number of patients in the 2 highest age groups, the percentage of patients aged ≥71 years with CIDP
and DM was statistically significantly higher than those without DM (P < 0.01). In addition, the treatment of CIDP patients without or with a concomitant diagnosis of DM was found to
be similar. Approximately 50% of patients were treated with IVIg (57% CIDP without DM
and 52% CIDP with DM), 23%–24% with steroids, 1%–2% with PE; and approximately
20%–23% received no treatment in both groups (Fig. 2). Although clinical data are not
available, one might hypothesize that these untreated patients had only mild disability and
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therefore, according to EFNS/PNS guidelines, would be managed with monitoring for
disease worsening (EFNS/PNS, 2010). Notably, steroid and IVIg use was similar between
both groups. As only claim data were available, we cannot comment on the responsiveness
of these patients to various treatments.
In an alternative analysis evaluating this database with less stringent inclusion criteria (ie, ≥2
CIDP claims reported at no particular time interval), the reliability of this dataset became
more evident. Without requiring the CIDP claims to be reported at least 90 days apart, we
found similar results to those derived from the more stringent analysis previously described.
A total of 3,399 patients had confirmed CIDP; 2,380 (70%) patients had CIDP without DM;
and 1,019 (30%) patients had CIDP with DM. Comparable to the data described in Fig. 1,
the age distribution derived from this less stringent analysis demonstrated: (A) CIDP without
DM was more common than CIDP with DM (P = 0.01) in patients aged <50 years; (B) there was no difference in patients aged 51 to 60 years for both groups (29% CIDP without DM
and 30% CIDP with DM, P = 0.36); however, (C) CIDP with DM was statistically significantly higher than CIDP without DM in patients aged >61 years (P = 0.01). Treatment of CIDP patients without or with a concomitant diagnosis of DM also appeared consistent
with data described in Fig. 2 (approximately 40% of patients were treated with IVIg, 27%
with steroids, 1%–2% with PE, and roughly 30% received no treatment).
Interestingly, the CIDP patient age distribution in this large United States database was
similar to the age distribution observed in an Italian epidemiological study (N = 4,334,225),
in which older patients had a higher prevalence of CIDP than younger patients (Chio et al.,
2007). We, thus, conclude that diabetes may be a common comorbidity along with CIDP in
patients older than 50 years. Despite the potential selection bias for fewer patients older than
65 years (due to a limited number of patients ≥65 years old enrolled in Medicare), we expect
that such bias would not only underestimate the prevalence of DM observed, but also
underestimate the associated prevalence of patients with CIDP and DM.
5. Treatment of CIDP with DM
At present, the decision on how to treat CIDP with DM is guided by treatment for CIDP
without DM. CIDP is the most common treatable autoimmune neuropathy (Mathey et al.,
2015); up to 80% of patients with CIDP respond to treatment. Clinical studies have shown
that corticosteroids, PE, and IVIg all have efficacy in CIDP (Dyck, Daube, O’Brien, et al.,
1986; Dyck, O’Brien, Oviatt, et al., 1982; Hahn, Bolton, Pillay, et al., 1996a; Hughes,
Donofrio, Bril, et al., 2008; Mehndiratta & Hughes, 2002; Rajabally, 2015). The EFNS/PNS
guidelines (EFNS/PNS, 2010) recommend IVIg or corticosteroids for sensory and motor
CIDP; IVIg for pure motor CIDP; and if IVIg and corticosteroids are both ineffective, PE
should be considered. Combination treatment or the addition of an immunosuppressant or
immunomodulatory drug may be considered if the response to IVIg, corticosteroids, or PE is
inadequate. Several clinical studies have shown that patients with CIDP and DM are also
responsive to immunological treatment (Cocito, Ciaramitaro, Isoardo, et al., 2002; Dunnigan
et al., 2014; Gorson et al., 2000; Jann, Bramerio, Facchetti, et al., 2009; Krendel, Costigan,
& Hopkins, 1995; Sharma, Cross, et al., 2002a; Stewart, McKelvey, Durcan, et al., 1996).
Treatment decisions depend on factors such as concomitant diseases, cost, therapeutic