ÓRgÃO O ICIAL DA SOCIEDADE PORTUgUESA DE REUMATOLOgIA
308
CARTA AO EDITOR
Ch onic hypona emia: a new isk ac o
o agili y ac u es in he elde ly?
ACTA REUMATOL PORT. 2015;40:308-309
To he Edi o ,
Mul iple isk ac o s o os eopo o ic ac u e, inclu -
ding os eopo osis and alls, a e widely known. I is also
clea ha os eopo o ic ac u es impose a signi ican
mo bidi y and mo ali y in he elde ly, wi h majo
mone a y cos s associa ed.
Recen s udies sugges ha ch onic hypona emia
(se um [Na+] < 135mEq/L), albei sligh (se um [Na+]
= 125-134 mEq/L), may be associa ed wi h alls, os-
eopo osis and ac u es. PubMed sea ch o “(“os eo-
po osis” OR “ ac u e” OR “ alls”) AND “hypona e -
mia”“ (Ma ch 1s 2014, las i e yea s, english) e ie ed
h ee dozen esul s.
Se e al s udies ha e shown associa ions be ween
ch onic hypona emia and alls, ac u es o os eo-
po osis:
• Falls incidence in elde ly people wi h mild ch onic
hypona emia is signi ican 1
• Hypona emia is no associa ed wi h lowe bone
mine al densi y1(despi e he ela ion be ween hy-
pona emia and os eopo osis sugges ed by a p e i-
ous c oss-sec ional su ey2)
• Hypona emia incidence in elde ly pa ien s admi ed
o ac u e seconda y o acciden al all is conside a -
ble3
• Hypona emia is e y p e alen in elde ly pa ien s
wi h agili y ac u e.4
Bu , can hypona emia pe se cause bone disease? In-
deed, se e al s udies ha e shown ha ch onic hy-
pona emia may be an independen isk ac o o alls,
ac u es and os eopo osis due o inc eased p obabili-
y o alls1[adjus ed odds a io (aOR) 1.35], os eo-
po osis2[aOR 2.85 o hip os eopo osis], ac u e3[OR
4.16] and os eopo o ic ac u e5[OR 1.46], and he in-
c eased isk o inciden non e eb al ac u e1[adjus -
ed haza d a io (aHR) 1.34 95% CI 1.08-1.68,
Hen iques M1
1. Medical Depa men , Physical and Rehabili a ion Medicine
Depa men , Na y’s Physical Educa ion Cen e; No h Lisbon
Hospi al Cen e – Sain Ma y’s Hospi al
p=0.009] and e eb al ac u e1(combined p e alen
and inciden ) [aOR 1.61, 95% CI 1.00-2.59, p=0.049].
Fu he mo e, ch onic hypona emia is associa ed wi h
inc eased likelihood o in-hospi al dea h a e hip ac-
u e (OR 3.64)6and inc eased all-cause mo ali y isk
(aHR 1.21, 95% CI 1.03-1.43, p=0.022)1.
Labo a o y s udies indica e ha hypona emia
s imu la es os eoclas ogenesis7and animal model s u -
dies associa e hypona emia wi h dec eased hickness
o co ical bone and inc eased numbe o os eoclas s2.
The e a e al eady p oposals o he mechanism o bone
disease induced by ch onic hypona emia in humans
(Figu e 1)8.
This ques ion seems o be p oblema ic conside ing
ha ch onic hypona emia is a common diso de in he
elde ly8and usually asymp oma ic (75-80% o cases7):
7.2% o pa ien s a ending o he i s ime in p ima y
ca e o 49.2% o hose obse ed o he i s ime in he
hospi al9, 10% o pa ien s admi ed o he eme gency
oom (ER),10 7% o ambula o y elde ly up o 53% o
ins i u ionalized elde ly2.
Mo eo e , he elde ly a e subjec o si ua ions o
g ea e p opensi y o ch onic hypona emia ins alla-
ion, as polypha macy (e.g. diu e ics, an idep essan s,
an iepilep ics, p o on pump inhibi o s) and diseases
(e.g. synd ome o inapp op ia e sec e ion o an idi-
u e ic ho mone (± 50% o ch onic hypona emia ca -
ses), diabe es melli us, hypo hy oidism, hepa ic ci -
hosis, conges i e hea ailu e, kidney disease)8.
Physicians who ollow elde ly pa ien s should be
awa e o he associa ion be ween bone disease and
ch o nic hypona emia. As he measu emen o se um
sodium is a simple, a ailable and inexpensi e p oce-
du e, i should be achie ed in elde ly pa ien s wi h in-
c eased isk o hypona emia, p esen ing clinical symp-
oms consis en wi h hypona aemia, o which a e ob-
se ed in he ER o bone inju y8.
Upon he hypona emia diagnosis i ’s necessa y o
es ablish he app op ia e ea men . In he asymp o -
ma ic cases i ’s ecommended, a leas , he iden i ica ion
ÓRgÃO O ICIAL DA SOCIEDADE PORTUgUESA DE REUMATOLOgIA
309
Hen iques M
o e e sible causes o p e en ecu ence and luid es -
ic ion o 0.5 o 1L/day. Selec i e asop essin ece p o
V2 an agonis s may be a ea men op ion in he u-
u e.
Bene i s o p e en ion, diagnosis and e ec i e ea -
men o ch onic hypona emia in alls, os eopo osis
and ac u e isk, as quali y o li e, a e ye o p o e8. Fo
his, new p ospec i e s udies a e needed.
Ch onic hypona emia may p esen i sel as a new
and impo an independen isk ac o o alls, ac u -
es and os eopo osis in he elde ly. Tha said, medical
communi y should be ale o his p oblem and in es
in p e en ion, diagnosis and ea men !
CoRREspondEnCE o
Moisés Hen iques
Es ada da Luz nº199, 6º D o
1600-155 Lisboa, Po ugal
E-mail: [email p o ec ed]
REFEREnCEs
1. Hoo n EJ, Ri adenei a F, an Meu s JB, e al. Mild hypona e-
mia as a isk ac o o ac u es: he Ro e dam S udy. J Bone
Mine Res. 2011;26(8):1822-1828.
2. Ve balis JG, Ba sony J, Sugimu a Y, e al. Hypona emia-indu-
ced os eopo osis. J Bone Mine Res. 2010;25(3):554-563.
3. Kengne FG, And es C, Sa a L, e al. Mild hypona emia and
isk o ac u e in he ambula o y elde ly. Q J Med. 2008;
101:583-588.
4. Cumming K, Hoyle GE, Hu chison JD, Soiza RL. P e alence, in-
cidence and e iology o hypona emia in elde ly pa ien s wi h
agili y ac u es. PLoS One. 2014;9(2):e88272.
5. A ampa zis S, Gae cke LM, Funk GC, e al. Diu e ic-induced
hypona emia and os eopo o ic ac u es in pa ien s admi ed
o he eme gency depa men . Ma u i as. 2013;75(1):81-86.
6. Hagino T, Ochiai S, Wa anabe Y, e al. Hypona emia a ad-
mission is associa ed wi h in-hospi al dea h in pa ien s wi h
hip ac u e. A ch O hop T auma Su g. 2013;133(4):507-511.
7. Ba sony J, Sugimu a Y, Ve balis JG. Os eoclas esponse o low
ex acellula sodium and he mechanism o hypona emia-in-
duced bone loss. J Biol Chem. 2011;286(12):10864-10875.
8. Ayus JC, Neg i AL, Kalan a -Zadeh K, Mo i z ML. Is ch onic
hypona emia a no el isk ac o o hip ac u e in he elde -
ly? Neph ol Dial T ansplan . 2012;27(10):3725-3731.
9. Hawkins RC. Age and gende as isk ac o s o hypona emia
and hype na emia. Clin Chim Ac a. 2003;337(1-2):169-172.
10. A ampa zis S, F auchige B, Fiedle GM, e al. Cha ac e is ics,
symp oms, and ou come o se e e dysna emias p esen on
hos pi al admission. Am J Med. 2012;125(11):1125.e1-1125.
e7.
In e io limi o se um
[Na+] o impai ed gai
(134mEq/L) and
educed a en ion
(132mEq/L)
1/3 o o al body Na+
is in he bones;
40% o bone [Na+]
is exchangeable o
blood ci cula ion
↓ gai balance +
↓ a en ion +
men al con usion
↓ bone mine aliza ion
+
↑ os eoclas s ac i i y
CNS impai men Os eopo osis
Falls Bone agili y
Ch onic Hipona emia
Bone ac u e
In e io limi o se um
[Na+] o impai ed gai
(134mEq/L) and
educed a en ion
(132mEq/L)
1/3 o o al body Na+
is in he bones;
40% o bone [Na+]
is exchangeable o
blood ci cula ion
↓ gai balance +
↓ a en ion +
men al con usion
↓ bone mine aliza ion
+
↑ os eoclas s ac i i y
CNS impai men Os eopo osis
Falls Bone agili y
Ch onic Hipona emia
Bone ac u e
FIGURE 1. Mechanism o bone disease induced by ch onic hypona emia in humans