(2021) 40:19
Durda‑Masny et al. J Physiol Anthropol
https://doi.org/10.1186/s40101-021-00269-7

ORIGINAL ARTICLE

Open Access

The determinants of survival among adults
with cystic fibrosis—a cohort study
Magdalena Durda‑Masny1, Joanna Goździk‑Spychalska2, Aleksandra John1, Wojciech Czaiński2,
Weronika Stróżewska1, Natalia Pawłowska1, Jolanta Wlizło2, Halina Batura‑Gabryel2 and Anita Szwed1*

Abstract
Background: Cystic fibrosis (CF) is one of the most common autosomal recessive diseases. Factors contributing todisease exacerbations and survival rate of CF patients are type of mutation in the CFTR gene, poor nutritional status,lung failure, and infection development by Pseudomonas aeruginosa. The study aimed to evaluate the relationshipbetween the severity of mutation, nutritional status, lung function, and Pseudomonas aeruginosa prevalence andsurvival rate in adult patients with cystic fibrosis.
Methods: A study of 124 (68 ♀ and 56 ♂) adults with CF aged 18–51 years were evaluated for (a) type of mutation in
the CFTR gene, (b) nutritional status (BMI), (c) lung function ­(FEV1%), and (d) Pseudomonas aeruginosa prevalence. For
statistical calculations, Kaplan-Meier analysis of survival, chi-squared test for multiple samples, and logistic regression
were used.
Results: The type of mutation (χ2 = 12.73, df = 3, p = 0.005), ­FEV1% (χ2 = 15.20, df = 2, p = 0.0005), Pseudomonas
aeruginosa prevalence (χ2 = 11.48, df = 3, p = 0.009), and BMI (χ2 = 31.08, df = 4, p < 0.000) significantly differentiatedthe probability of survival of patients with CF. The shortest life expectancy was observed in patients with a severe typeof mutation on both alleles, ­FEV1% < 40, subjects in whom Pseudomonas culture was extensively drug-resistant or
pandrug-resistant, and patients whose BMI was lower than 18.5 kg/m2. The period from 30 to 40 years of age was themost critical in CF adults’ lifespan. The risk of adults with CF death doubled with Pseudomonas aeruginosa prevalence(OR = 2.06, 95% CI 1.29; 2.28) and eightfold when the bacteria acquired antibiotic resistance (OR = 8.11, 95% CI 1.67;
38.15).
Conclusions: All factors included in the study were significantly related to the survival rate of patients with cystic
fibrosis.
Keywords: Cystic fibrosis, Lung function, Life expectancy, BMI, Pseudomonas aeruginosa
Introduction
Cystic fibrosis (CF) is one of the most common autosomal recessive diseases caused by 2102 mutations of the
CFTR gene (http://​www.​genet.​sickk​ids.​on.​ca/​Stati​stics​
Page.​html). The type of mutation is considered as one of*Correspondence: aniszwed@amu.edu.pl
1
Institute of Human Biology and Evolution, Faculty of Biology, Adam
Mickiewicz University, Uniwersytetu Poznanskiego 6 St, 61‑614 Poznan,
PolandFull list of author information is available at the end of the article

the most important factors determining the survival rate.
Severe mutations of at least one allele reduce the survivalof patients with CF and are associated with lung function
deterioration [1]. It is already known that the other factors contributing to disease exacerbations are lung failure
and infection development [2]. One of the most important pathogens in adults with CF, causing chronic infection and evolve into antibiotic resistance, is Pseudomonas
aeruginosa. Previous studies showed that P. aeruginosa,
mainly multidrug resistance culture, is associated withmorbidity and mortality in patients with CF [3]. The© The Author(s) 2021. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which
permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to theoriginal author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images orother third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line
to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory
regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of thislicence, visit http://​creat​iveco​mmons.​org/​licen​ses/​by/4.​0/. The Creative Commons Public Domain Dedication waiver (http://​creat​iveco​
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Durda‑Masny et al. J Physiol Anthropol(2021) 40:19

decline in lung function is also associated with poor
nutritional status [4–8]. Lung function, nutritional status,
and the presence of P. aeruginosa are interrelated, and thestudies by John et al. [9] have shown that decreased lungfunction ­(FEV1% < 40), undernutrition (BMI < 18.5), andsevere mutation type are associated with a higher probability of P. aeruginosa acquisition and with the higher
level of its resistance to antibiotic treatment.
Until now, research on the factors affecting the survival rate of patients with CF has focused mainly on thepediatric population. Due to advances in medical care,
the number of adults with CF is steadily growing [10]. A
multicenter report on patients with CF at the age of 40
and above, conducted by Hodson et al. [11], showed thata significant number of patients reach the age of 40 or
more. However, the answer to the question of why some
CF patients live longer than others is still unclear, which,
together with the increasing number of adult patients,
generates the need for research on the factors affecting
the survival rate in this group. Hence, the study aimed toevaluate the relationship between lung function, P. aeruginosa prevalence, nutritional status, and the severity ofmutation type and survival rate in adult patients with CF.

Methods
The study we conducted was a cohort study in its nature.
The same group of patients recruited for the research in2010 was subjected to annual examinations for the next
Table 1 The number of patients in each age cohort at the
beginning of the study and the number of patients who diedduring the course of the study
Patients’ age cohorts
at the beginning of the
study

Number

Percent

Number of patients
who died during the
study

18–23

60

48.39

8

24–29

35

28.23

8

30–35

22

17.74

3

36–41

7

5.64

2

Page 2 of 99 years. At the beginning of the study, the cohort consisted of 124 patients aged 18 to 41 years old, treated at
the Department of Pulmonology, Allergology, and Respiratory Oncology, Poznan University of Medical Science, in Poland. The group consisted of 68 women and
56 men. For the period of 9 years, i.e., until 2019, thevalues of respiratory parameters, nutritional status, thepresence of P. aeruginosa, and the degree of its resistance to antibiotics were analyzed in the studied group, atleast annually for each patient. A total of 21 people diedduring the research, and it was the only reason why thesize of the study group decreased over time (Table 1).
The complete data was obtained from all other patients
included in the study. Statistical analyses were performed on the last measurements obtained at the end of
the study for living patients, or on the last measurements
obtained before the death, for patients who died during
the study.
Adults with CF who either underwent a lung transplant, were pregnant, smoked, used systemic glucocorticosteroids, or had pulmonary exacerbation during 4
weeks preceding the study were excluded.
Information about the type of mutation, nutritional
status, lung function, and P. aeruginosa prevalence wascollected. Data about the type of mutation of the CFTR
gene were obtained from the archives of medical recordsof the Department of Pulmonology, Allergology, and Respiratory Oncology of the University of Medical Sciencesin Poznan. To systematize the type of mutation present in each patient, all subjects were divided into fourgroups based on severity, in accordance with the widely
accepted mutation classification in the CFTR gene [12,13] (Table 2): (1) patients with severe types of mutation(I, II, III mutation classes) on both alleles (I–III/I–III), (2)heterozygous patients with a severe type of mutation on
one allele and mild (I–III/IV–V) or unclassified mutation(other mutations, including those unknown) on anotherallele (I–III/u), (3) patients with mild types of mutation(IV and V mutation classes) on both alleles (IV–V/IV–V),
and (4) unclassified mutations (u/u) (Table 3).

Table 2 Classification of the CFTR gene mutations (Lubamba et al. [12]; De Boeck et al. [13])Class

Consequences

List of mutations attributed

I

CFTR is not synthesized because of stop codons or splicing defects.

G542X, W1282X, R553X, 3950delT

II

CFTR is synthesized but in an immature and is mostly degraded by the ubiquitinproteasomal pathway.

F508del, N1303K

III

CFTR is synthesized and transported to the plasma membrane, but its activation andregulation by ATPor cAMP are disrupted.

G551D, G178R, S549N, S549R, G551S, G970R,
G1244E, S1251N, S1255P, G1349D

IV

CFTR is synthesized and expressed at the plasma membrane, but chloride conduct‑
ance is reduced.

R334W, G314E, R347P, D1152H

V

CFTR synthesis or processing is partly defective.

3849+ 10 kb C→T, 3272-26 A→G, 2789+5G→A

Unclassified

All other mutations, including those unknown

Durda‑Masny et al. J Physiol Anthropol(2021) 40:19

Page 3 of 9Lung function was determined by a spirometry test
using a diagnostic Jaeger MasterScreen system (Erich Jaeger GmbH; Würzburg, Germany). Data about predicted
forced expiratory volume in 1 s (­FEV1%) were collectedfrom 124 patients. According to the Cystic Fibrosis Trust[14], all subjects were divided into three subgroups basedon ­FEV1%: (1) patients within the norm (­ FEV1% > 70),(2) with moderate pulmonary impairment (­FEV1%
70–40), and (3) severe pulmonary impairment (­ FEV1% < 40)(Table 3).
The microbiological examination carried out by amicrobiological laboratory was performed in all patients.
Microbiological data allowed us to classify patients into
the following groups (Table 3): (1) Pseudomonas culturenegative and (2) Pseudomonas culture-positive. Drug susceptibility was measured using the Eucast v.6.0 method.
Pseudomonas culture-positive patients were divided into
the following: 2a, patients in whom all antibiotics used
to treat infections caused by bacterial colonization were
fully effective (non-multidrug resistant/ non-MDR); 2b,
subjects in whom Pseudomonas culture was insensitive
Table 3 Number and percentage of adult CF people in the
category of CFTR mutation, nutritional status, lung function, andPseudomonas aeruginosa infection
Variable

NumberN (%)

Genotype
I–III/I–III

40

32.26

I–III/IV–V or I–III/u

31

25.00

IV–V/IV–V

24

19.35

u/u

29

23.39

FEV1%
 ­FEV1% > 70

31

25.00

 ­FEV1% 70–40

47

37.90

 ­FEV1% < 40

46

37.10

Pseudomonas aeruginosa
Pseudomonas culture-negative

36

29.03

Non-MDR

37

29.84

MDR

24

19.36

XDR/PDR

27

21.77

Nutritional status
BMI ≥ 25

BMI 18.5–24.9

5

4.03

74

59.68

BMI 17–18.49 (class II malnutrition)

24

19.35

BMI 16–16.99 (class I malnutrition)

9

7.26

BMI < 16 (emaciation)

12

9.68

I–III/I–III patients with severe types of mutation on both alleles, I–III/IV–V or I–III/upatients with a severe type of mutation on one allele and mild or unclassified
mutation on another allele, IV–V/IV–V patients with mild types of mutation
on both alleles, u/u patients with unclassified mutations on both alleles, BMI
body mass index, FEV1% forced expiratory volume in one second, Non-MDR
non-multidrug-resistant patients, MDR multidrug-resistant patients, PDR+XDR
pandrug-resistant and extensively drug-resistant patients(resistant or moderately sensitive) to at least one antibiotic from at least three groups of antibacterial drugs(multidrug-resistant (MDR)); and 2c, patients in whom
Pseudomonas culture was extensively drug-resistant(XDR) or pandrug-resistant (PDR). The above division
was made by the definitions from the work of Magiorakos et al. [15].
Nutritional status was determined based on body massindex (BMI) that was calculated by dividing body weightby height squared (kg/m2). To obtain this data, anthropometric measurements were taken. The body height wasmeasured without shoes and in underwear, with a GMP
anthropometer, with a measurement accuracy of 1 mm.
Body weight was measured using a medical scale with ameasurement accuracy of 100 g. To exclude measurement
errors, all measurements were performed by one experienced researcher. Based on the BMI, a group of adults
with CF was divided into five (Table 3): emaciation (BMI< 16), class II undernutrition (BMI = 16–16.99), class I
undernutrition (BMI = 17–18.49), within the norm (BMI
= 18.5–24.9), and overweight (BMI ≥ 25).
The study was performed with the approval of the local
research ethics committee (resolution No. 51/17). All
participants had provided their written informed consent
of participation in this study.
The effect of nutritional status, lung function, P. aeruginosa prevalence, and the severity of mutation type on
survival was determined with the Kaplan-Meier method.
Differences in the survival rate within the study groups
were assessed with the chi-squared test for multiple
samples. To determine the risk of death depending on
the type of mutation, nutritional status, lung function,and the impact of P. aeruginosa on survival rate, logistic
regression was used. p-values < 0.05 defined statisticallysignificant differences. Statistical analysis was performed
with the Statistica 12.0 data analysis software system(StatSoft Polska).

Results
Survival analysis using the Kaplan-Meier method has
shown that the survival of patients with CF stood at 100%
up to the age of 20; then, it started to decline gradually(Fig. 1). The decline in the probability curve showed that
almost 27% of patients will not exceed the age of 30 yearsof life, and almost 48% of patients will not exceed the ageof 40.
In our study group, all patients who lived to the age of
40 are still alive (N = 7). At the time of writing this article, three subjects were 41 years old, and four were 42, 43,
49, and 51 years old.
The probability of survival was different depending on
the severity of the mutation type (χ2 = 12.73, df = 3, p

Durda‑Masny et al. J Physiol Anthropol(2021) 40:19

Page 4 of 9

Fig. 1 Kaplan-Meier plot for the age of patients with cystic fibrosis= 0.005). The average life expectancy of patients with
I–III/I–III mutations was the lowest. The survival curve(Fig. 2) in this group decreased after the age of 20, andthe probability of death before the age of 35 was almost
60%. In this group, there were no people over 40 years ofage. Subjects with I–III/IV–V or I–III/u mutations lived
longer than in the I–III/I–III group. The survival curvein this group began to decline after the age of 23 years,
and the probability of death before reaching the age of
32 was over 40%. It is seen that the curve stabilized after
the age of 32, and it is worth mentioning that there was
one person in this group who has reached the age of 49.
Among patients with I–IV/I––IV mutations, the decline
in the survival curve was small, and the curve stabilized
after 25 years of age. However, it can be seen that the 40thyear of life was critical for their survival, since only threepatients managed to pass over this age. In the group withu/u mutations, there were no cases of death recorded,
and the survival curve was stable. Two patients from thisgroup were over the age of 40, and one was over the ageof 50 (Fig. 2).
The factor that significantly differentiated patientsin terms of life expectancy was also lung function (χ2= 15.20, df = 2, p = 0.0005). Those patients with CF
whose ­FEV1% > 70% lived longest. The mortality rate
was equal to 0, and additionally, there were people over
40 and 50 years old in this group. The survival curve of
CF adults with ­FEV1% between 40 and 70% was steeper.

The chance for those patients to reach the age of 40 wasin the range of 50%. Approximately 20% will die before
the age of 34 and another 28% of patients before reaching the age of 40. The lowest life expectancy applied topatients with ­FEV1% < 40. The probability of survival inthis group began to decrease after reaching the age of 20.
The survival curve was very steep up to the critical pointof 26 years of age. In this group, the probability of death
before the age of 30 was almost 50%, and only about 35%
of patients have a chance to live to be 40 years old (Fig. 3).
Kaplan-Meier survival analysis showed also that P. aeruginosa significantly influenced the length of the patient’s
life (χ2 = 11.48, df = 3, p = 0.009). The longest average
life expectancy was indicated among Pseudomonas culture-negative and non-MDR patients (Fig. 4). The survival curve was comparatively stable in both groups. The
probability of exceeding 40 years of age in these patientswas approximately 80%. The average life expectancy was
lower in MDR patients. The probability of survival was
decreasing after 22 years of life, and the probability ofexceeding the age of 30 was less than 60%. The survival
of XDR and PDR patients was the most detrimental. The
probability of survival was decreasing steadily from theage of 20 up to the age of 40. Furthermore, nutritional
status assessed by BMI (Fig. 5) significantly influenced
the length of patients’ life (χ2 = 31.08, df = 4, p < 0.000).
There were no deceased among overweight patients, andtheir survival curve was stable. The survival curve of theDurda‑Masny et al. J Physiol Anthropol(2021) 40:19

Page 5 of 9

Fig. 2 Probability functions depicting the age of patients with cystic fibrosis in categories of mutation

Fig. 3 Probability functions depicting the age of patients with cystic fibrosis in categories of lung function (­ FEV1%)

properly nourished patients (BMI 18.5–24.99 kg/m2) wascharacterized by a slight decline of up to the age of 30.
The highest decrease occurred between the age of 30

and 40. In a group of adults with CF within the norm,
the life span exceeded 50 years. In turn, in all groups ofundernourished subjects, the survival curve dropped

Durda‑Masny et al. J Physiol Anthropol(2021) 40:19

Page 6 of 9

Fig. 4 Probability functions depicting the age of patients in categories of Pseudomonas aeruginosa infection and antibiotic resistance (P. aeruginosa
4 categories)

Fig. 5 Probability functions depicting the age of patients with cystic fibrosis in categories of nutritional status (BMI)Durda‑Masny et al. J Physiol Anthropol(2021) 40:19

significantly after reaching the age of 20. The life expectancy of the respondents in these groups did not exceed
34 years of age. The survival curves of all three subgroups
were steep. All patients with BMI < 16.00 died before
reaching the age of 30. The probability of survival among
emaciated adults was significantly lower than among
those from the I and II classes of undernutrition.
The results of logistic regression analysis showed thatthe risk of death increased almost sixfold when F­ EV1%
fell below normal (OR = 5.83, 95% CI 2.51; 13.52, p <0.001), more than four times when BMI fell below normal(OR = 4.17, 95% CI 1.65; 10.50, p = 0.002), and twice inthe case of having a severe CFTR gene mutation (OR =2.35, 95% CI 1.17; 4.71, p = 0.01). The risk of death for apatient with CF increased twice with P. aeruginosa prevalence (OR = 2.06, 95% CI 1.29; 2.28, p = 0.002) and eighttimes if the bacteria acquired antibiotic resistance (OR =8.11, 95% CI 1.67; 38.15, p = 0.008).

Discussion
The probability of survival among adults with CF is a
result of both genetic and environmental factors contributing to the course of the disease. Our research isone of the first to show the impact of the factors suchas the severity of mutation in the CFTR gene, nutritional status, lung function, and P. aeruginosa prevalenceon survival rate in adult patients with cystic fibrosis. In
our study, group survival curve started to decrease after
20 and became stable after 40 years of age. Most of thedeaths took place in the period between the age of 30
and 40 years. The fundamental factor contributing to theaverage life expectancy was the type of mutation. Since
the early nineties of the twentieth century, mutation
causing CF has been categorized into five classes basedon molecular mechanisms of CFTR chloride channel
dysfunction [16], which corresponds to the phenotypeof the disease. Our research indicated the difference inlife expectancy between the groups of patients with CF
distinguished according to the severity of the mutation.
Patients with a mild mutation on one allele or both alleles
lived longer than subjects from the group with severetypes of mutation on both alleles. Similar results havebeen shown by McKone et al. [17], who found that themortality rate was lower among patients with IV and V
mutation classes compared to II class (F508del homozygotes). Currently, ongoing molecular studies concerning
cell and gene therapy are a milestone in CF treatment, as
the new strategies of therapy allow transferring the wildtype CFTR gene to the airway cells [18]. Apart from genetherapy, an important role is played by the early determination of the CFTR gene mutation type then followed bya prompt implementation of modern treatment methods. Neonatal screening allows for early diagnosis andPage 7 of 9

therefore contributes to the better growth of patients andtheir better pulmonary outcomes [19]. Based on statistics, a patient with CF that gets a proper treatment andundergoes an adequate medical care that corresponds
to the latest knowledge regarding the effects of a given
mutation, at the early stage of disease, has a greater
chance for a longer life compared to patients who lived
in previous decades. Our study showed, however, thatindependent of other factors, a strong influence of thegenetic factor on the rate of disease progression is stillobserved. The most critical life period in adults with CF
characterized by a severe type of mutation falls within aperiod between the ages of 20 and 30 years. Similarly, for
I–III/IV–V, patients’ crucial stage of the disease occurs
between the ages of 25 to 31. It can be therefore summed
up that the strongest impact of CFTR mutation in a CF
patients’ life expectancy is being observed from the age of
20 up to about 31. This suggests that in adult CF patients,
the type of mutation may still be the most important
predictor for the prognosis of the disease. However, in
our studies, some patients who shared the same typeof mutation had a different disease severity. Taking thisfact into account, the non-genetic factors that contributeto the survival rate of patients should not be underestimated [20, 21]. Our results indicate that the reduction of
the value of each of the analyzed non-genetic variables
below the specified threshold, i.e., FEV1% < 40%, BMI< 18.5, and XDR or PDR Pseudomonas prevalence, entails
a number of negative consequences inevitably leading
to the patient’s death. Therefore, when predicting CF
patient’s survival, each of the variables analyzed in thesestudies should be taken into account.
The maintenance of proper lung function and prevention of undernutrition is considered as a priority in CF
treatment. These factors provide the basis for keeping apatient in a state of stability. The results of this and previous studies [22] confirm the impact of lung function
and nutritional status on the survival of adults with CF,
showing that severe and moderate pulmonary impairment has a major impact on average life expectancy.
Critical moments concern exclusively adults with F­ EV1%< 70%. Our results are consistent with the findings ofother authors [23, 24]. The significance of lung function,
considered as an important factor contributing to CF
patients’ mortality, has been emphasized already by many
researchers [25, 26]. Henry et al. [27] after performing
stepwise regression showed that lung function describedby ­FEV1% has the main effect on a patient’s survival.
According to Belkin et al. [28], ­FEV1% < 30% increases
the risk of death among both adult and pediatric patientswith CF. Similarly, our analysis showed that ­FEV1% < 40%
is critical for patients’ mortality, making it almost impossible for them to live into the age of 40. Furthermore, inDurda‑Masny et al. J Physiol Anthropol(2021) 40:19

a group of patients with severe pulmonary impairment,
the majority of subjects die before the age of 30. Effective
pulmonary disease therapy can, therefore, form the basis
for preventing exacerbations and contribute to better
survival of a patient with CF. Our probability of survival
analysis highlights the problem of serious pulmonary
exacerbations occurring between the age of 20 and 40.
The survival curve for patients after the age of 40 was
mostly stable. A study by Simmonds et al. [23] comparing adult patients with CF aged ≥ 40 with those who died
before the age of 30 showed also that patients without
any respiratory disease and with higher BMI were more
likely to live into their 40s.
Another factor affecting the course of lung diseases arepathogen infections. Among adults with CF, P. aeruginosa is the most frequently occurring pathogen, affecting approximately 80% of the patients [29]. Our studies
showed that the presence of P. aeruginosa decreases average life expectancy. Previous studies conducted amongchildren confirm the adverse effect of P. aeruginosa on
survival, lung function, and weight percentiles [30]. The
consequences of P. aeruginosa presence in adults are
not only similarly negative but also tend to exacerbate.
Courtney et al. [26] showed that P. aeruginosa infection
significantly affects CF adults’ mortality. Their studies
revealed that the majority of patients who died (98%) had
a chronic infection caused by this pathogen. We showedthat the most critical point in survival of CF patient iswhen P. aeruginosa becomes fully or partly resistant to
antibiotic treatment. Lechtzin et al. [29] obtained similar results, confirming that multiple antibiotic-resistantP. aeruginosa is associated with ­FEV1% reduction andpulmonary disease.
Moreover, exacerbations in lung function may severely
affect the nutritional status of people with CF. Our study
showed very explicit differences in the probability ofsurvival with nutritional status. A significant number ofpatients in a group with a BMI < 18.5 died before eventurning the age of 30. Undernourished adults with CF
lived no longer than 34 years old. Undernutrition is to alarge degree a consequence of pancreas insufficiency, fatmalabsorption, micronutrient deficiencies, and increased
energy expenditure [31]. Furthermore, energy losses
in the course of lung disease exceed patient’s dietaryintake. In turn, poor nutritional status may be a subsequent considerable factor in the CF adult lifespan. This isconfirmed by previous studies [21–25]. Research by Yen
et al. [7] showed that higher body weight in childhood
is associated with fewer pulmonary exacerbations andbetter survival through the first 18 years of life. According to Courtney et al. [26], BMI is not a reliable predictor of mortality but has a significant impact on the courseof pulmonary disease. However, studies conducted byPage 8 of 9

Sharma et al. [32] showed that wasting has a significant
impact on the probability of survival in CF adult patients,
regardless of lung function.
In this paper, we have shown the relationships between
selected factors influencing disease progression and survival in adult CF patients. It is important, however, that
all these factors interact with each other, creating theso-called vicious circle, which has already been shownin studies on a similar group of patients [9]. Therefore,
it is important to take into account all the analyzed factors when monitoring the course of the disease in adultpatients with cystic fibrosis.

Conclusions
In summary, we can assume that all factors includedin the study were significantly related to the survival
rate of patients with cystic fibrosis. The shortest average life expectancy was indicated in people exhibiting
severe mutation type, F­ EV1% < 40%, BMI < 18.5, and
XDR or PDR P. aeruginosa prevalence. In comparison,among patients with lung function within the norm and
BMI above 25, no one has died. Adult CF patients over
40 years of age, remained in groups of an unknown ormild type of mutation, with normal or moderate lungfunction, with no P. aeruginosa, or with strains susceptible to antibiotic treatment. Our study allowed us todetermine that the period between 30 and 40 years of age
is the most critical in CF adults’ life span. Furthermore,most exacerbations occurred over the period between 20
and 35 years of age.
Abbreviations
CF: Cystic fibrosis; CFTR: Cystic fibrosis transmembrane conductance regulator;
FEV1%: Predicted forced expiratory volume in 1 s (percentage of predictedvalue); non-MDR: Non-multidrug resistant; MDR: Multidrug-resistant; XDR:Extensively drug-resistant; PDR: Pandrug-resistant; BMI: Body mass index.
Acknowledgements
Not applicable
Authors’ contributions
Magdalena Durda-Masny: conceptualization, investigation, formal analysis,
and writing—review and editing. Joanna Goździk-Spychalska: conceptualiza‑
tion, investigation, supervision, and writing—review and editing. Aleksandra
John: data curation, formal analysis, validation, and writing—review andediting. Wojciech Czaiński: investigation and writing—review and editing.
Weronika Stróżewska: investigation and writing—review and editing. Natalia
Pawłowska: investigation and writing—review and editing. Jolanta Wlizło:
investigation and writing—review and editing. Halina Batura-Gabryel: supervi‑
sion and writing—review and editing. Anita Szwed: conceptualization, project
administration, formal analysis, supervision, and writing—original draft. The
authors read and approved the final manuscript.
Authors’ information
Not applicable
Funding
This research received no external funding.

Durda‑Masny et al. J Physiol Anthropol(2021) 40:19

Availability of data and materials
The datasets used and/or analyzed during the current study are available fromthe corresponding author on reasonable request.

Declarations
Ethics approval and consent to participate
The study was conducted according to the guidelines of the Declarationof Helsinki and approved by the local research Bioethics Committee at the
Poznan Medical University of Karol Marcinkowski (resolution No. 51/17).
Consent for publication
Informed consent was obtained from all subjects involved in the study.
Competing interests
The authors declare that they have no competing interests.
Author details
1
Institute of Human Biology and Evolution, Faculty of Biology, Adam Mick‑
iewicz University, Uniwersytetu Poznanskiego 6 St, 61‑614 Poznan, Poland.
2
Department of Pulmonology, Allergology and Respiratory Oncology, Poznan
University of Medical Sciences, Szamarzewskiego 82/84, 60‑569 Poznań,Poland.
Received: 7 May 2021 Accepted: 22 October 2021

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